Processing-in-memory (PIM) system and operating methods of the PIM system

ABSTRACT

A processing-in-memory (PIM) system includes a PIM device and a PIM controller. The PIM device includes a first storage region, a second storage region, and a multiplication/accumulation (MAC) operator configured to receive first data and second data from the first and second storage regions, respectively, to perform a MAC arithmetic operation. The PIM controller controls a memory mode and a MAC mode of the PIM device. The PIM controller is configured to generate and transmit a memory command to the PIM device in the memory mode. In addition, the PIM controller is configured to generate and transmit first to fifth MAC commands to the PIM device in the MAC mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 17/027,276, filed on Sep. 21, 2020, which claimsbenefit of U.S. Provisional Application No. 62/958,226, filed on Jan. 7,2020, and claims priority to Korean Application No. 10-2020-0006903,filed on Jan. 17, 2020, which are incorporated herein by reference intheir entirety.

BACKGROUND 1. Technical Field

Various embodiments of the present disclosure relate toprocessing-in-memory (PIM) systems and, more particularly, to PIMsystems including a PIM device and a controller and methods of operatingthe PIM systems.

2. Related Art

Recently, interest in artificial intelligence (AI) has been increasingnot only in the information technology industry but also in thefinancial and medical industries. Accordingly, in various fields,artificial intelligence, more precisely, the introduction of deeplearning, is considered and prototyped. In general, techniques foreffectively learning deep neural networks (DNNs) or deep networks havingincreased layers as compared with general neural networks to utilize thedeep neural networks (DNNs) or the deep networks in pattern recognitionor inference are commonly referred to as deep learning.

One cause of this widespread interest may be the improved performance ofprocessors performing arithmetic operations. To improve the performanceof artificial intelligence, it may be necessary to increase the numberof layers constituting a neural network in the artificial intelligenceto educate the artificial intelligence. This trend has continued inrecent years, which has led to an exponential increase in the amount ofcomputation required for the hardware that actually does thecomputation. Moreover, if the artificial intelligence employs a generalhardware system including memory and a processor which are separatedfrom each other, the performance of the artificial intelligence may bedegraded due to limitation of the amount of data communication betweenthe memory and the processor. In order to solve this problem, a PIMdevice in which a processor and memory are integrated in onesemiconductor chip has been used as a neural network computing device.Because the PIM device directly performs arithmetic operationsinternally, data processing speed in the neural network may be improved.

SUMMARY

A processing-in-memory (PIM) system according to an embodiment of thepresent disclosure includes a PIM device and a PIM controller. The PIMdevice includes a first storage region, a second storage region, and amultiplication/accumulation (MAC) operator receiving first data andsecond data from the first and second storage regions, respectively, toperform a MAC arithmetic operation. The PIM controller controls a memorymode and a MAC mode of the PIM device. The PIM controller is configuredto generate and transmit a memory command to the PIM device in thememory mode and is configured to generate and transmit first to fifthMAC commands to the PIM device in the MAC mode.

A processing-in-memory (PIM) system according to an embodiment of thepresent disclosure includes a PIM device and a PIM controller. The PIMdevice includes a storage region, a global buffer, and amultiplication/accumulation (MAC) operator, wherein the MAC operator issuitable for receiving first data and second data from the storageregion and the global buffer, respectively, to perform a MAC arithmeticoperation. The PIM controller is configured to control a memory mode anda MAC mode of the PIM device. The PIM controller is configured togenerate and transmit a memory command to the PIM device in the memorymode and is configured to generate and transmit first to third MACcommands to the PIM device in the MAC mode.

A processing-in-memory (PIM) system according to an embodiment of thepresent disclosure includes a PIM device and a PIM controller. The PIMdevice includes a data storage region and an arithmetic circuit. Thearithmetic circuit is configured to receive first data and second datafrom the data storage region to perform an arithmetic operation with thefirst data and the second data. The PIM controller is configured tocontrol a memory mode and an arithmetic mode of the PIM device. The PIMcontroller is configured to generate and transmit a memory command tothe PIM device in the memory mode. And the PIM controller is configuredto generate and transmit a plurality of arithmetic commands to the PIMdevice in the arithmetic mode.

According to an embodiment of the present disclosure is a method ofoperating a processing-in-memory (PIM) system including a PIM device forperforming a multiplication/accumulation (MAC) arithmetic operation anda PIM controller for controlling the MAC arithmetic operation of the PIMdevice. The method includes iteratively performing while an incrementedinteger ‘R’ with an initial value of 1 is less than or equal to a fixedinteger ‘M’: transmitting a first MAC command from the PIM controller tothe PIM device to output elements in an R^(th) row of an ‘M×N’ weightmatrix stored in a first storage region of the PIM device for the MACarithmetic operation to a MAC operator of the PIM device (where, ‘M’ and‘N’ are natural numbers greater than ‘1’); transmitting a second MACcommand from the PIM controller to the PIM device to output elements ina first column of an ‘N×1’ vector matrix stored in a second storageregion of the PIM device for the MAC arithmetic operation to the MACoperator of the PIM device; transmitting a third MAC command from thePIM controller to the PIM device to execute an input latch operation forlatching the elements in the R^(th) row of the weight matrix in the MACoperator; transmitting a fourth MAC command from the PIM controller tothe PIM device to execute an input latch operation for latching theelements in the first column of the vector matrix in the MAC operator;performing a matrix multiplying calculation of the elements in theR^(th) row of the weight matrix and the elements in the first column ofthe vector matrix latched by the MAC operator; transmitting a fifth MACcommand from the PIM controller to the PIM device to execute an outputlatch operation of result data of the matrix multiplying calculation inthe MAC operator; transmitting a sixth MAC command from the PIMcontroller to the PIM device to output result data of the output latchoperation from the MAC operator; and increasing the integer ‘R’ by one.

According to an embodiment of the present disclosure is a method ofoperating a processing-in-memory (PIM) system including a PIM device forperforming a multiplication/accumulation (MAC) arithmetic operation anda PIM controller for controlling the MAC arithmetic operation of the PIMdevice. The method includes iteratively performing while an incrementedinteger ‘R’ with an initial value of 1 is less than or equal to a fixedinteger ‘M’: transmitting a first MAC command from the PIM controller tothe PIM device to output elements in an R^(th) row of an ‘M×N’ weightmatrix stored in a storage region of the PIM device for the MACarithmetic operation to a MAC operator of the PIM device (where, ‘M’ and‘N’ are natural numbers greater than ‘1’); outputting elements in afirst column of an ‘N×1’ vector matrix stored in a global buffer of thePIM device for the MAC arithmetic operation to the MAC operator of thePIM device; transmitting a second MAC command from the PIM controller tothe PIM device to execute an input latch operation for latching theelements in the R^(th) row of the weight matrix and the elements in thefirst column of the vector matrix in the MAC operator; performing amatrix multiplying calculation of the elements in the R^(th) row of theweight matrix and the elements in the first column of the vector matrixlatched by the MAC operator; transmitting a third MAC command from thePIM controller to the PIM device to execute an output latch operation ofresult data of the matrix multiplying calculation in the MAC operator;transmitting a fourth MAC command from the PIM controller to the PIMdevice to output result data of the output latch operation from the MACoperator; and increasing the integer ‘R’ by one.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features of the disclosed technology are illustrated in variousembodiments with reference to the attached drawings.

FIG. 1 is a block diagram illustrating a PIM system according to anembodiment of the present disclosure.

FIG. 2 is a block diagram illustrating a PIM system according to a firstembodiment of the present disclosure.

FIG. 3 illustrates MAC commands outputted from a MAC command generatorof a PIM controller included in a PIM system according to a firstembodiment of the present disclosure.

FIG. 4 is a block diagram illustrating an example of a configuration ofa MAC operator of a PIM device included in a PIM system according to afirst embodiment of the present disclosure.

FIG. 5 illustrates an example of a MAC arithmetic operation performed ina PIM system according to a first embodiment of the present disclosure.

FIG. 6 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 5 in a PIM system according to a firstembodiment of the present disclosure.

FIGS. 7 to 13 are block diagrams illustrating processes of the MACarithmetic operation illustrated in FIG. 5 in a PIM system according toa first embodiment of the present disclosure.

FIG. 14 illustrates another example of a MAC arithmetic operationperformed in a PIM system according to a first embodiment of the presentdisclosure.

FIG. 15 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 14 in a PIM system according to a firstembodiment of the present disclosure.

FIG. 16 illustrates an example of a configuration of a MAC operator forperforming the MAC arithmetic operation of FIG. 14 in a PIM systemaccording to a first embodiment of the present disclosure.

FIG. 17 illustrates yet another example of a MAC arithmetic operationperformed in a PIM system according to a first embodiment of the presentdisclosure.

FIG. 18 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 17 in a PIM system according to a firstembodiment of the present disclosure.

FIG. 19 illustrates an example of a configuration of a MAC operator forperforming the MAC arithmetic operation of FIG. 17 in a PIM systemaccording to a first embodiment of the present disclosure.

FIG. 20 is a block diagram illustrating a PIM system according to asecond embodiment of the present disclosure.

FIG. 21 illustrates MAC commands outputted from a MAC command generatorof a PIM controller included in a PIM system according to a secondembodiment of the present disclosure.

FIG. 22 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 5 in a PIM system according to a secondembodiment of the present disclosure.

FIGS. 23 to 26 are block diagrams illustrating processes of the MACarithmetic operation illustrated in FIG. 5 in a PIM system according toa second embodiment of the present disclosure.

FIG. 27 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 14 in a PIM system according to a secondembodiment of the present disclosure.

FIG. 28 is a flowchart illustrating processes of the MAC arithmeticoperation illustrated in FIG. 17 in a PIM system according to a secondembodiment of the present disclosure.

FIG. 29 is a block diagram illustrating a PIM system according to yetanother embodiment of the present disclosure.

FIG. 30 is a block diagram illustrating a PIM system according to stillanother embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following description of embodiments, it will be understood thatthe terms “first” and “second” are intended to identify elements, butnot used to define a particular number or sequence of elements. Inaddition, when an element is referred to as being located “on,” “over,”“above,” “under,” or “beneath” another element, it is intended to mean arelative positional relationship, but not used to limit certain cases inwhich the element directly contacts the other element, or at least oneintervening element is present therebetween. Accordingly, the terms suchas “on,” “over,” “above,” “under,” “beneath,” “below,” and the like thatare used herein are for the purpose of describing particular embodimentsonly and are not intended to limit the scope of the present disclosure.Further, when an element is referred to as being “connected” or“coupled” to another element, the element may be electrically ormechanically connected or coupled to the other element directly, or maybe electrically or mechanically connected or coupled to the otherelement indirectly with one or more additional elements therebetween.

Various embodiments are directed to PIM systems and methods of operatingthe PIM systems.

FIG. 1 is a block diagram illustrating a PIM system according to anembodiment of the present disclosure. As illustrated in FIG. 1 , the PIMsystem 1 may include a PIM device 10 and a PIM controller 20. The PIMdevice 10 may include a data storage region 11, an arithmetic circuit12, an interface (I/F) 13-1, and a data (DQ) input/output (I/O) pad13-2. The data storage region 11 may include a first storage region anda second storage region. In an embodiment, the first storage region andthe second storage region may be a first memory bank and a second memorybank, respectively. In another embodiment, the first data storage regionand the second storage region may be a memory bank and buffer memory,respectively. The data storage region 11 may include a volatile memoryelement or a non-volatile memory element. For an embodiment, the datastorage region 11 may include both a volatile memory element and anon-volatile memory element.

The arithmetic circuit 12 may perform an arithmetic operation on thedata transferred from the data storage region 11. In an embodiment, thearithmetic circuit 12 may include a multiplying-and-accumulating (MAC)operator. The MAC operator may perform a multiplying calculation on thedata transferred from the data storage region 11 and perform anaccumulating calculation on the multiplication result data. After MACoperations, the MAC operator may output MAC result data. The MAC resultdata may be stored in the data storage region 11 or output from the PIMdevice 10 through the data I/O pad 13-2.

The interface 13-1 of the PIM device 10 may receive a command CMD andaddress ADDR from the PIM controller 20. The interface 13-1 may outputthe command CMD to the data storage region 11 or the arithmetic circuit12 in the PIM device 10. The interface 13-1 may output the address ADDRto the data storage region 11 in the PIM device 10. The data I/O pad13-2 of the PIM device 10 may function as a data communication terminalbetween a device external to the PIM device 10, for example the PIMcontroller 20, and the data storage region 11 included in the PIM device10. The external device to the PIM device 10 may correspond to the PIMcontroller 20 of the PIM system 1 or a host located outside the PIMsystem 1. Accordingly, data outputted from the host or the PIMcontroller 20 may be inputted into the PIM device 10 through the dataI/O pad 13-2.

The PIM controller 20 may control operations of the PIM device 10. In anembodiment, the PIM controller 20 may control the PIM device 10 suchthat the PIM device 10 operates in a memory mode or an arithmetic mode.In the event that the PIM controller 20 controls the PIM device 10 suchthat the PIM device 10 operates in the memory mode, the PIM device 10may perform a data read operation or a data write operation for the datastorage region 11. In the event that the PIM controller 20 controls thePIM device 10 such that the PIM device 10 operates in the arithmeticmode, the arithmetic circuit 12 of the PIM device 10 may receive firstdata and second data from the data storage region 11 to perform anarithmetic operation. In the event that the PIM controller 20 controlsthe PIM device 10 such that the PIM device 10 operates in the arithmeticmode, the PIM device 10 may also perform the data read operation and thedata write operation for the data storage region 11 to execute thearithmetic operation. The arithmetic operation may be a deterministicarithmetic operation performed during a predetermined fixed time. Theword “predetermined” as used herein with respect to a parameter, such asa predetermined fixed time or time period, means that a value for theparameter is determined prior to the parameter being used in a processor algorithm. For some embodiments, the value for the parameter isdetermined before the process or algorithm begins. In other embodiments,the value for the parameter is determined during the process oralgorithm but before the parameter is used in the process or algorithm.

The PIM controller 20 may be configured to include command queue logic21, a scheduler 22, a command (CMD) generator 23, and an address (ADDR)generator 25. The command queue logic 21 may receive a request REQ froman external device (e.g., a host of the PIM system 1) and store thecommand queue corresponding to the request REQ in the command queuelogic 21. The command queue logic 21 may transmit information on astorage status of the command queue to the scheduler 22 whenever thecommand queue logic 21 stores the command queue. The command queuestored in the command queue logic 21 may be transmitted to the commandgenerator 23 according to a sequence determined by the scheduler 22. Thecommand queue logic 21, and also the command queue logic 210 of FIGS. 2and 20 , may be implemented as hardware, software, or a combination ofhardware and software. For example, the command queue logic 21 and/or210 may be a command queue logic circuit operating in accordance with analgorithm and/or a processor executing command queue logic code.

The scheduler 22 may adjust a sequence of the command queue when thecommand queue stored in the command queue logic 21 is outputted from thecommand queue logic 21. In order to adjust the output sequence of thecommand queue stored in the command queue logic 21, the scheduler 22 mayanalyze the information on the storage status of the command queueprovided by the command queue logic 21 and may readjust a processsequence of the command queue so that the command queue is processedaccording to a proper sequence.

The command generator 23 may receive the command queue related to thememory mode of the PIM device 10 and the MAC mode of the PIM device 10from the command queue logic 21. The command generator 23 may decode thecommand queue to generate and output the command CMD. The command CMDmay include a memory command for the memory mode or an arithmeticcommand for the arithmetic mode. The command CMD outputted from thecommand generator 23 may be transmitted to the PIM device 10.

The command generator 23 may be configured to generate and transmit thememory command to the PIM device 10 in the memory mode. The commandgenerator 23 may be configured to generate and transmit a plurality ofarithmetic commands to the PIM device 10 in the arithmetic mode. In oneexample, the command generator 23 may be configured to generate andoutput first to fifth arithmetic commands with predetermined timeintervals in the arithmetic mode. The first arithmetic command may be acontrol signal for reading the first data out of the data storage region11. The second arithmetic command may be a control signal for readingthe second data out of the data storage region 11. The third arithmeticcommand may be a control signal for latching the first data in thearithmetic circuit 12. The fourth arithmetic command may be a controlsignal for latching the second data in the arithmetic circuit 12. Andthe fifth MAC command may be a control signal for latching arithmeticresult data of the arithmetic circuit 12.

The address generator 25 may receive address information from thecommand queue logic 21 and generate the address ADDR for accessing aregion in the data storage region 11. In an embodiment, the address ADDRmay include a bank address, a row address, and a column address. Theaddress ADDR outputted from the address generator 25 may be inputted tothe data storage region 11 through the interface (I/F) 13-1.

FIG. 2 is a block diagram illustrating a PIM system 1-1 according to afirst embodiment of the present disclosure. As illustrated in FIG. 2 ,the PIM system 1-1 may include a PIM device 100 and a PIM controller200. The PIM device 100 may include a first memory bank (BANK1) 111, asecond memory bank (BANK1) 112, a MAC operator 120, an interface (I/F)131, and a data input/output (I/O) pad 132. For an embodiment, the MACoperator 120 represents a MAC operator circuit. The first memory bank(BANK1) 111, the second memory bank (BANK1) 112, and the MAC operator120 included in the PIM device 100 may constitute one MAC unit. Inanother embodiment, the PIM device 100 may include a plurality of MACunits. The first memory bank (BANK1) 111 and the second memory bank(BANK1) 112 may represent a memory region for storing data, for example,a DRAM device. Each of the first memory bank (BANK1) 111 and the secondmemory bank (BANK1) 112 may be a component unit which is independentlyactivated and may be configured to have the same data bus width as dataI/O lines in the PIM device 100. In an embodiment, the first and secondmemory banks 111 and 112 may operate through interleaving such that anactive operation of the first and second memory banks 111 and 112 isperformed in parallel while another memory bank is selected. Each of thefirst and second memory banks 111 and 112 may include at least one cellarray which includes memory unit cells located at cross points of aplurality of rows and a plurality of columns.

Although not shown in the drawings, a core circuit may be disposedadjacent to the first and second memory banks 111 and 112. The corecircuit may include X-decoders XDECs and Y-decoders/IO circuitsYDEC/IOs. An X-decoder XDEC may also be referred to as a word linedecoder or a row decoder. The X-decoder XDEC may receive a row addressADD_R from the PIM controller 200 and may decode the row address ADD_Rto select and enable one of the rows (i.e., word lines) coupled to theselected memory bank. Each of the Y-decoders/IO circuits YDEC/IOs mayinclude a Y-decoder YDEC and an I/O circuit JO. The Y-decoder YDEC mayalso be referred to as a bit line decoder or a column decoder. TheY-decoder YDEC may receive a column address ADDR_C from the PIMcontroller 200 and may decode the column address ADDR_C to select andenable at least one of the columns (i.e., bit lines) coupled to theselected memory bank. Each of the I/O circuits may include an I/O senseamplifier for sensing and amplifying a level of a read datum outputtedfrom the corresponding memory bank during a read operation for the firstand second memory banks 111 and 112. In addition, the I/O circuit mayinclude a write driver for driving a write datum during a writeoperation for the first and second memory banks 111 and 112.

The interface 131 of the PIM device 100 may receive a memory commandM_CMD, MAC commands MAC_CMDs, a bank selection signal BS, and therow/column addresses ADDR_R/ADDR_C from the PIM controller 200. Theinterface 131 may output the memory command M_CMD, together with thebank selection signal BS and the row/column addresses ADDR_R/ADDR_C, tothe first memory bank 111 or the second memory bank 112. The interface131 may output the MAC commands MAC_CMDs to the first memory bank 111,the second memory bank 112, and the MAC operator 120. In such a case,the interface 131 may output the bank selection signal BS and therow/column addresses ADDR_R/ADDR_C to both of the first memory bank 111and the second memory bank 112. The data I/O pad 132 of the PIM device100 may function as a data communication terminal between a deviceexternal to the PIM device 100 and the MAC unit (which includes thefirst and second memory banks 111 and 112 and the MAC operator 120)included in the PIM device 100. The external device to the PIM device100 may correspond to the PIM controller 200 of the PIM system 1-1 or ahost located outside the PIM system 1-1. Accordingly, data outputtedfrom the host or the PIM controller 200 may be inputted into the PIMdevice 100 through the data I/O pad 132.

The PIM controller 200 may control operations of the PIM device 100. Inan embodiment, the PIM controller 200 may control the PIM device 100such that the PIM device 100 operates in a memory mode or a MAC mode. Inthe event that the PIM controller 200 controls the PIM device 100 suchthat the PIM device 100 operates in the memory mode, the PIM device 100may perform a data read operation or a data write operation for thefirst memory bank 111 and the second memory bank 112. In the event thatthe PIM controller 200 controls the PIM device 100 such that the PIMdevice 100 operates in the MAC mode, the PIM device 100 may perform aMAC arithmetic operation for the MAC operator 120. In the event that thePIM controller 200 controls the PIM device 100 such that the PIM device100 operates in the MAC mode, the PIM device 100 may also perform thedata read operation and the data write operation for the first andsecond memory banks 111 and 112 to execute the MAC arithmetic operation.

The PIM controller 200 may be configured to include command queue logic210, a scheduler 220, a memory command generator 230, a MAC commandgenerator 240, and an address generator 250. The command queue logic 210may receive a request REQ from an external device (e.g., a host of thePIM system 1-1) and store a command queue corresponding to the requestREQ in the command queue logic 210. The command queue logic 210 maytransmit information on a storage status of the command queue to thescheduler 220 whenever the command queue logic 210 stores the commandqueue. The command queue stored in the command queue logic 210 may betransmitted to the memory command generator 230 or the MAC commandgenerator 240 according to a sequence determined by the scheduler 220.When the command queue outputted from the command queue logic 210includes command information requesting an operation in the memory modeof the PIM device 100, the command queue logic 210 may transmit thecommand queue to the memory command generator 230. On the other hand,when the command queue outputted from the command queue logic 210 iscommand information requesting an operation in the MAC mode of the PIMdevice 100, the command queue logic 210 may transmit the command queueto the MAC command generator 240. Information on whether the commandqueue relates to the memory mode or the MAC mode may be provided by thescheduler 220.

The scheduler 220 may adjust a timing of the command queue when thecommand queue stored in the command queue logic 210 is outputted fromthe command queue logic 210. In order to adjust the output timing of thecommand queue stored in the command queue logic 210, the scheduler 220may analyze the information on the storage status of the command queueprovided by the command queue logic 210 and may readjust a processsequence of the command queue such that the command queue is processedaccording to a proper sequence. The scheduler 220 may output andtransmit to the command queue logic 210 information on whether thecommand queue outputted from the command queue logic 210 relates to thememory mode of the PIM device 100 or relates to the MAC mode of the PIMdevice 100. In order to obtain the information on whether the commandqueue outputted from the command queue logic 210 relates to the memorymode or the MAC mode, the scheduler 220 may include a mode selector 221.The mode selector 221 may generate a mode selection signal includinginformation on whether the command queue stored in the command queuelogic 210 relates to the memory mode or the MAC mode, and the scheduler220 may transmit the mode selection signal to the command queue logic210.

The memory command generator 230 may receive the command queue relatedto the memory mode of the PIM device 100 from the command queue logic210. The memory command generator 230 may decode the command queue togenerate and output the memory command M_CMD. The memory command M_CMDoutputted from the memory command generator 230 may be transmitted tothe PIM device 100. In an embodiment, the memory command M_CMD mayinclude a memory read command and a memory write command. When thememory read command is outputted from the memory command generator 230,the PIM device 100 may perform the data read operation for the firstmemory bank 111 or the second memory bank 112. Data which are read outof the PIM device 100 may be transmitted to an external device throughthe data I/O pad 132. The read data outputted from the PIM device 100may be transmitted to a host through the PIM controller 200. When thememory write command is outputted from the memory command generator 230,the PIM device 100 may perform the data write operation for the firstmemory bank 111 or the second memory bank 112. In such a case, data tobe written into the PIM device 100 may be transmitted from the host tothe PIM device 100 through the PIM controller 200. The write datainputted to the PIM device 100 may be transmitted to the first memorybank 111 or the second memory bank 112 through the data I/O pad 132.

The MAC command generator 240 may receive the command queue related tothe MAC mode of the PIM device 100 from the command queue logic 210. TheMAC command generator 240 may decode the command queue to generate andoutput the MAC commands MAC_CMDs. The MAC commands MAC_CMDs outputtedfrom the MAC command generator 240 may be transmitted to the PIM device100. The data read operation for the first memory bank 111 and thesecond memory bank 112 of the PIM device 100 may be performed by the MACcommands MAC_CMDs outputted from the MAC command generator 240, and theMAC arithmetic operation of the MAC operator 120 may also be performedby the MAC commands MAC_CMDs outputted from the MAC command generator240. The MAC commands MAC_CMDs and the MAC arithmetic operation of thePIM device 100 according to the MAC commands MAC_CMDs will be describedin detail with reference to FIG. 3 .

The address generator 250 may receive address information from thecommand queue logic 210. The address generator 250 may generate the bankselection signal BS for selecting one of the first and second memorybanks 111 and 112 and may transmit the bank selection signal BS to thePIM device 100. In addition, the address generator 250 may generate therow address ADDR_R and the column address ADDR_C for accessing a region(e.g., memory cells) in the first or second memory bank 111 or 112 andmay transmit the row address ADDR_R and the column address ADDR_C to thePIM device 100.

FIG. 3 illustrates the MAC commands MAC_CMDs outputted from the MACcommand generator 240 included in the PIM system 1-1 according to thefirst embodiment of the present disclosure. As illustrated in FIG. 3 ,the MAC commands MAC_CMDs may include first to sixth MAC commandsignals. In an embodiment, the first MAC command signal may be a firstMAC read signal MAC_RD_BK0, the second MAC command signal may be asecond MAC read signal MAC_RD_BK1, the third MAC command signal may be afirst MAC input latch signal MAC_L1, the fourth MAC command signal maybe a second MAC input latch signal MAC_L2, the fifth MAC command signalmay be a MAC output latch signal MAC_L3, and the sixth MAC commandsignal may be a MAC latch reset signal MAC_L_RST.

The first MAC read signal MAC_RD_BK0 may control an operation forreading first data (e.g., weight data) out of the first memory bank 111to transmit the first data to the MAC operator 120. The second MAC readsignal MAC_RD_BK1 may control an operation for reading second data(e.g., vector data) out of the second memory bank 112 to transmit thesecond data to the MAC operator 120. The first MAC input latch signalMAC_L1 may control an input latch operation of the weight datatransmitted from the first memory bank 111 to the MAC operator 120. Thesecond MAC input latch signal MAC_L2 may control an input latchoperation of the vector data transmitted from the second memory bank 112to the MAC operator 120. If the input latch operations of the weightdata and the vector data are performed, the MAC operator 120 may performthe MAC arithmetic operation to generate MAC result data correspondingto the result of the MAC arithmetic operation. The MAC output latchsignal MAC_L3 may control an output latch operation of the MAC resultdata generated by the MAC operator 120. And, the MAC latch reset signalMAC_L_RST may control an output operation of the MAC result datagenerated by the MAC operator 120 and a reset operation of an outputlatch included in the MAC operator 120.

The PIM system 1-1 according to the present embodiment may be configuredto perform a deterministic MAC arithmetic operation. The term“deterministic MAC arithmetic operation” used in the present disclosuremay be defined as the MAC arithmetic operation performed in the PIMsystem 1-1 during a predetermined fixed time. Thus, the MAC commandsMAC_CMDs transmitted from the PIM controller 200 to the PIM device 100may be sequentially generated with fixed time intervals. Accordingly,the PIM controller 200 does not require any extra end signals of variousoperations executed for the MAC arithmetic operation to generate the MACcommands MAC_CMDs for controlling the MAC arithmetic operation. In anembodiment, latencies of the various operations executed by MAC commandsMAC_CMDs for controlling the MAC arithmetic operation may be set to havefixed values in order to perform the deterministic MAC arithmeticoperation. In such a case, the MAC commands MAC_CMDs may be sequentiallyoutputted from the PIM controller 200 with fixed time intervalscorresponding to the fixed latencies.

For example, the MAC command generator 240 is configured to output thefirst MAC command at a first point in time. The MAC command generator240 is configured to output the second MAC command at a second point intime when a first latency elapses from the first point in time. Thefirst latency is set as the time it takes to read the first data out ofthe first storage region based on the first MAC command and to outputthe first data to the MAC operator. The MAC command generator 240 isconfigured to output the third MAC command at a third point in time whena second latency elapses from the second point in time. The secondlatency is set as the time it takes to read the second data out of thesecond storage region based on the second MAC command and to output thesecond data to the MAC operator. The MAC command generator 240 isconfigured to output the fourth MAC command at a fourth point in timewhen a third latency elapses from the third point in time. The thirdlatency is set as the time it takes to latch the first data in the MACoperator based on the third MAC command. The MAC command generator 240is configured to output the fifth MAC command at a fifth point in timewhen a fourth latency elapses from the fourth point in time. The fourthlatency is set as the time it takes to latch the second data in the MACoperator based on the fourth MAC command and to perform the MACarithmetic operation of the first and second data which are latched inthe MAC operator. The MAC command generator 240 is configured to outputthe sixth MAC command at a sixth point in time when a fifth latencyelapses from the fifth point in time. The fifth latency is set as thetime it takes to perform an output latch operation of MAC result datagenerated by the MAC arithmetic operation.

FIG. 4 illustrates an example of the MAC operator 120 of the PIM device100 included in the PIM system 1-1 according to the first embodiment ofthe present disclosure. Referring to FIG. 4 , MAC operator 120 may beconfigured to include a data input circuit 121, a MAC circuit 122, and adata output circuit 123. The data input circuit 121 may include a firstinput latch 121-1 and a second input latch 121-2. The MAC circuit 122may include a multiplication logic circuit 122-1 and an addition logiccircuit 122-2. The data output circuit 123 may include an output latch123-1, a transfer gate 123-2, a delay circuit 123-3, and an inverter123-4. In an embodiment, the first input latch 121-1, the second inputlatch 121-2, and the output latch 123-1 may be realized usingflip-flops.

The data input circuit 121 of the MAC operator 120 may be synchronizedwith the first MAC input latch signal MAC_L1 to latch first data DA1transferred from the first memory bank 111 to the MAC circuit 122through an internal data transmission line. In addition, the data inputcircuit 121 of the MAC operator 120 may be synchronized with the secondMAC input latch signal MAC_L2 to latch second data DA2 transferred fromthe second memory bank 112 to the MAC circuit 122 through anotherinternal data transmission line. Because the first MAC input latchsignal MAC_L1 and the second MAC input latch signal MAC_L2 aresequentially transmitted from the MAC command generator 240 of the PIMcontroller 200 to the MAC operator 120 of the PIM device 100 with apredetermined time interval, the second data DA2 may be inputted to theMAC circuit 122 of the MAC operator 120 after the first data DA1 isinputted to the MAC circuit 122 of the MAC operator 120.

The MAC circuit 122 may perform the MAC arithmetic operation of thefirst data DA1 and the second data DA2 inputted through the data inputcircuit 121. The multiplication logic circuit 122-1 of the MAC circuit122 may include a plurality of multipliers 122-11. Each of themultipliers 122-11 may perform a multiplying calculation of the firstdata DA1 outputted from the first input latch 121-1 and the second dataDA2 outputted from the second input latch 121-2 and may output theresult of the multiplying calculation. Bit values constituting the firstdata DA1 may be separately inputted to the multipliers 122-11.Similarly, bit values constituting the second data DA2 may also beseparately inputted to the multipliers 122-11. For example, if the firstdata DA1 is represented by an ‘N’-bit binary stream, the second data DA2is represented by an ‘N’-bit binary stream, and the number of themultipliers 122-11 is ‘M’, then ‘N/M’-bit portions of the first data DA1and ‘N/M’-bit portions of the second data DA2 may be inputted to each ofthe multipliers 122-11.

The addition logic circuit 122-2 of the MAC circuit 122 may include aplurality of adders 122-21. Although not shown in the drawings, theplurality of adders 122-21 may be disposed to provide a tree structureincluding a plurality of stages. Each of the adders 122-21 disposed at afirst stage may receive two sets of multiplication result data from twoof the multipliers 122-11 included in the multiplication logic circuit122-1 and may perform an adding calculation of the two sets ofmultiplication result data to output the addition result data. Each ofthe adders 122-21 disposed at a second stage may receive two sets ofaddition result data from two of the adders 122-21 disposed at the firststage and may perform an adding calculation of the two sets of additionresult data to output the addition result data. The adder 122-21disposed at a last stage may receive two sets of addition result datafrom two adders 122-21 disposed at the previous stage and may perform anadding calculation of the two sets of addition result data to output theaddition result data. Although not shown in the drawings, the additionlogic circuit 122-2 may further include an additional adder forperforming an accumulative adding calculation of MAC result data DA_MACoutputted from the adder 122-21 disposed at the last stage and previousMAC result data DA_MAC stored in the output latch 123-1 of the dataoutput circuit 123.

The data output circuit 123 may output the MAC result data DA_MACoutputted from the MAC circuit 122 to a data transmission line.Specifically, the output latch 123-1 of the data output circuit 123 maybe synchronized with the MAC output latch signal MAC_L3 to latch the MACresult data DA_MAC outputted from the MAC circuit 122 and to output thelatched data of the MAC result data DA_MAC. The MAC result data DA_MACoutputted from the output latch 123-1 may be fed back to the MAC circuit122 for the accumulative adding calculation. In addition, the MAC resultdata DA_MAC may be inputted to the transfer gate 123-2. The output latch123-1 may be initialized if a latch reset signal LATCH_RST is inputtedto the output latch 123-1. In such a case, all of data latched by theoutput latch 123-1 may be removed. In an embodiment, the latch resetsignal LATCH_RST may be activated by generation of the MAC latch resetsignal MAC_L_RST and may be inputted to the output latch 123-1.

The MAC latch reset signal MAC_L_RST outputted from the MAC commandgenerator 240 may be inputted to the transfer gate 123-2, the delaycircuit 123-3, and the inverter 123-4. The inverter 123-4 may inverselybuffer the MAC latch reset signal MAC_L_RST to output the inverselybuffered signal of the MAC latch reset signal MAC_L_RST to the transfergate 123-2. The transfer gate 123-2 may transfer the MAC result dataDA_MAC from the output latch 123-1 to the data transmission line inresponse to the MAC latch reset signal MAC_L_RST. The delay circuit123-3 may delay the MAC latch reset signal MAC_L_RST by a certain timeto generate and output a latch control signal PINSTB.

FIG. 5 illustrates an example of the MAC arithmetic operation performedin the PIM system 1-1 according to the first embodiment of the presentdisclosure. As illustrated in FIG. 5 , the MAC arithmetic operationperformed by the PIM system 1-1 may be executed though a matrixcalculation. Specifically, the PIM device 100 may execute a matrixmultiplying calculation of an ‘M×N’ weight matrix (e.g., ‘8×8’ weightmatrix) and a ‘N×1’ vector matrix (e.g., ‘8×1’ vector matrix) accordingto control of the PIM controller 200 (where, ‘M’ and ‘N’ are naturalnumbers). Elements W0.0, . . . , and W7.7 constituting the weight matrixmay correspond to the first data DA1 inputted to the MAC operator 120from the first memory bank 111. Elements X0.0, . . . , and X7.0constituting the vector matrix may correspond to the second data DA2inputted to the MAC operator 120 from the second memory bank 112. Eachof the elements W0.0, . . . , and W7.7 constituting the weight matrixmay be represented by a binary stream having a plurality of bit values.In addition, each of the elements X0.0, . . . , and X7.0 constitutingthe vector matrix may also be represented by a binary stream having aplurality of bit values. The number of bits included in each of theelements W0.0, . . . , and W7.7 constituting the weight matrix may beequal to the number of bits included in each of the elements X0.0, . . ., and X7.0 constituting the vector matrix.

The matrix multiplying calculation of the weight matrix and the vectormatrix may be appropriate for a multilayer perceptron-type neuralnetwork structure (hereinafter, referred to as an ‘MLP-type neuralnetwork’). In general, the MLP-type neural network for executing deeplearning may include an input layer, a plurality of hidden layers (e.g.,at least three hidden layers), and an output layer. The matrixmultiplying calculation (i.e., the MAC arithmetic operation) of theweight matrix and the vector matrix illustrated in FIG. 5 may beperformed in one of the hidden layers. In a first hidden layer of theplurality of hidden layers, the MAC arithmetic operation may beperformed using vector data inputted to the first hidden layer. However,in each of second to last hidden layers among the plurality of hiddenlayers, the MAC arithmetic operation may be performed using acalculation result of the previous hidden layer as the vector data.

FIG. 6 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 5 , which are performed inthe PIM system 1-1 according to the first embodiment of the presentdisclosure. In addition, FIGS. 7 to 13 are block diagrams illustratingthe processes of the MAC arithmetic operation illustrated in FIG. 5 ,which are performed in the PIM system 1-1 according to the firstembodiment of the present disclosure. Referring to FIGS. 6 to 13 ,before the MAC arithmetic operation is performed, the first data (i.e.,the weight data) may be written into the first memory bank 111 at a step301. Thus, the weight data may be stored in the first memory bank 111 ofthe PIM device 100. In the present embodiment, it may be assumed thatthe weight data are the elements W0.0, . . . , and W7.7 constituting theweight matrix of FIG. 5 . The integer before the decimal point is oneless than a row number, and the integer after the decimal point is oneless than a column number. Thus, for example, the weight W0.0 representsthe element of the first row and the first column of the weight matrix.

At a step 302, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-1 to the PIM controller 200 of thePIM system 1-1. An inference request, in some instances, may be based onuser input. An inference request may initiate a calculation performed bythe PIM system 1-1 to reach a determination based on input data. In anembodiment, if no inference request signal is transmitted to the PIMcontroller 200, the PIM system 1-1 may be in a standby mode until theinference request signal is transmitted to the PIM controller 200.Alternatively, if no inference request signal is transmitted to the PIMcontroller 200, the PIM system 1-1 may perform operations (e.g., dataread/write operations) other than the MAC arithmetic operation in thememory mode until the inference request signal is transmitted to the PIMcontroller 200. In the present embodiment, it may be assumed that thesecond data (i.e., the vector data) are transmitted together with theinference request signal. In addition, it may be assumed that the vectordata are the elements X0.0, . . . , and X7.0 constituting the vectormatrix of FIG. 5 . If the inference request signal is transmitted to thePIM controller 200 at the step 302, then the PIM controller 200 maywrite the vector data transmitted with the inference request signal intothe second memory bank 112 at a step 303. Accordingly, the vector datamay be stored in the second memory bank 112 of the PIM device 100.

At a step 304, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC read signal MAC_RD_BK0 to thePIM device 100, as illustrated in FIG. 7 . In such a case, the addressgenerator 250 of the PIM controller 200 may generate and transmit thebank selection signal BS and the row/column address ADDR_R/ADDR_C to thePIM device 100. The bank selection signal BS may be generated to selectthe first memory bank 111 of the first and second memory banks 111 and112. Thus, the first MAC read signal MAC_RD_BK0 may control the dataread operation for the first memory bank 111 of the PIM device 100. Thefirst memory bank 111 may output and transmit the elements W0.0, . . . ,and W0.7 in the first row of the weight matrix of the weight data storedin a region of the first memory bank 111, which is selected by therow/column address ADDR_R/ADDR_C, to the MAC operator 120 in response tothe first MAC read signal MAC_RD_BK0. In an embodiment, the datatransmission from the first memory bank 111 to the MAC operator 120 maybe executed through a global input/output (hereinafter, referred to as‘GIO’) line which is provided as a data transmission path in the PIMdevice 100. Alternatively, the data transmission from the first memorybank 111 to the MAC operator 120 may be executed through a first bankinput/output (hereinafter, referred to as ‘BIO’) line which is providedspecifically for data transmission between the first memory bank 111 andthe MAC operator 120.

At a step 305, the MAC command generator 240 of the PIM controller 200may generate and transmit the second MAC read signal MAC_RD_BK1 to thePIM device 100, as illustrated in FIG. 8 . In such a case, the addressgenerator 250 of the PIM controller 200 may generate and transmit thebank selection signal BS for selecting the second memory bank 112 andthe row/column address ADDR_R/ADDR_C to the PIM device 100. The secondMAC read signal MAC_RD_BK1 may control the data read operation for thesecond memory bank 112 of the PIM device 100. The second memory bank 112may output and transmit the elements X0.0, . . . , and X7.0 in the firstcolumn of the vector matrix corresponding to the vector data stored in aregion of the second memory bank 112, which is selected by therow/column address ADDR_R/ADDR_C, to the MAC operator 120 in response tothe second MAC read signal MAC_RD_BK1. In an embodiment, the datatransmission from the second memory bank 112 to the MAC operator 120 maybe executed through the GIO line in the PIM device 100. Alternatively,the data transmission from the second memory bank 112 to the MACoperator 120 may be executed through a second BIO line which is providedspecifically for data transmission between the second memory bank 112and the MAC operator 120.

At a step 306, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC input latch signal MAC_L1 to thePIM device 100, as illustrated in FIG. 9 . The first MAC input latchsignal MAC_L1 may control the input latch operation of the first datafor the MAC operator 120 of the PIM device 100. The elements W0.0, . . ., and W0.7 in the first row of the weight matrix may be inputted to theMAC circuit 122 of the MAC operator 120 by the input latch operation, asillustrated in FIG. 11 . The MAC circuit 122 may include the pluralityof multipliers 122-11 (e.g., eight multipliers 122-11), the number ofwhich is equal to the number of columns of the weight matrix. In such acase, the elements W0.0, . . . , and W0.7 in the first row of the weightmatrix may be inputted to the eight multipliers 122-11, respectively.

At a step 307, the MAC command generator 240 of the PIM controller 200may generate and transmit the second MAC input latch signal MAC_L2 tothe PIM device 100, as illustrated in FIG. 10 . The second MAC inputlatch signal MAC_L2 may control the input latch operation of the seconddata for the MAC operator 120 of the PIM device 100. The elements X0.0,. . . , and X7.0 in the first column of the vector matrix may beinputted to the MAC circuit 122 of the MAC operator 120 by the inputlatch operation, as illustrated in FIG. 11 . In such a case, theelements X0.0, . . . , and X7.0 in the first column of the vector matrixmay be inputted to the eight multipliers 122-11, respectively.

At a step 308, the MAC circuit 122 of the MAC operator 120 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. For example,the scalar product is calculated of the R^(th) ‘1×N’ row vector of the‘M×N’ weight matrix and the ‘N×1’ vector matrix as an ‘R×1’ element ofthe ‘M×1’ MAC result matrix. For R=1, the scalar product of the firstrow of the weight matrix and the first column of the vector matrix shownin FIG. 5 isW0.0*X0.0+W0.1*X1.0+W0.2*X2.0+W0.3*X3.0+W0.4*X4.0+W0.5*X5.0+W0.6*X6.0+W0.7*X7.0.Specifically, each of the multipliers 122-11 of the multiplication logiccircuit 122-1 may perform a multiplying calculation of the inputteddata, and the result data of the multiplying calculation may be inputtedto the addition logic circuit 122-2. The addition logic circuit 122-2,as illustrated in FIG. 11 , may include four adders 122-21A disposed ata first stage, two adders 122-21B disposed at a second stage, and anadder 122-21C disposed at a third stage.

Each of the adders 122-21A disposed at the first stage may receiveoutput data of two of the multipliers 122-11 and may perform an addingcalculation of the output data of the two multipliers 122-11 to outputthe result of the adding calculation. Each of the adders 122-21Bdisposed at the second stage may receive output data of two of theadders 122-21A disposed at the first stage and may perform an addingcalculation of the output data of the two adders 122-21A to output theresult of the adding calculation. The adder 122-21C disposed at thethird stage may receive output data of two of the adders 122-21Bdisposed at the second stage and may perform an adding calculation ofthe output data of the two adders 122-21B to output the result of theadding calculation. The output data of the addition logic circuit 122-2may correspond to result data (i.e., MAC result data) of the MACarithmetic operation of the first row included in the weight matrix andthe column included in the vector matrix. Thus, the output data of theaddition logic circuit 122-2 may correspond to an element MAC0.0 locatedat a first row of an ‘8×1’ MAC result matrix having eight elements ofMAC0.0, . . . , and MAC7.0, as illustrated in FIG. 5 . The output dataMAC0.0 of the addition logic circuit 122-2 may be inputted to the outputlatch 123-1 disposed in the data output circuit 123 of the MAC operator120, as described with reference to FIG. 4 .

At a step 309, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 100, as illustrated in FIG. 12 . The MAC output latch signalMAC_L3 may control the output latch operation of the MAC result dataMAC0.0 performed by the MAC operator 120 of the PIM device 100. The MACresult data MAC0.0 inputted from the MAC circuit 122 of the MAC operator120 may be outputted from the output latch 123-1 in synchronization withthe MAC output latch signal MAC_L3, as described with reference to FIG.4 . The MAC result data MAC0.0 outputted from the output latch 123-1 maybe inputted to the transfer gate 123-2 of the data output circuit 123.

At a step 310, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 100, as illustrated in FIG. 13 . The MAC latch reset signalMAC_L_RST may control an output operation of the MAC result data MAC0.0generated by the MAC operator 120 and a reset operation of the outputlatch included in the MAC operator 120. As described with reference toFIG. 4 , the transfer gate 123-2 receiving the MAC result data MAC0.0from the output latch 123-1 of the MAC operator 120 may be synchronizedwith the MAC latch reset signal MAC_L_RST to output the MAC result dataMAC0.0. In an embodiment, the MAC result data MAC0.0 outputted from theMAC operator 120 may be stored into the first memory bank 111 or thesecond memory bank 112 through the first BIO line or the second BIO linein the PIM device 100.

At a step 311, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed during the previous steps, therow number of the weight matrix may change from ‘1’ to ‘2’ at the step311. At a step 312, whether the row number changed at the step 311 isgreater than the row number of the last row (i.e., the eighth row of thecurrent example) of the weight matrix may be determined. Because the rownumber of the weight matrix is changed to ‘2’ at the step 311, a processof the MAC arithmetic operation may be fed back to the step 304.

If the process of the MAC arithmetic operation is fed back to the step304 from the step 312, then the same processes as described withreference to the steps 304 to 310 may be executed again for theincreased row number of the weight matrix. That is, as the row number ofthe weight matrix changes from ‘1’ to ‘2’, the MAC arithmetic operationmay be performed for the second row of the weight matrix instead of thefirst row of the weight matrix with the vector matrix. If the process ofthe MAC arithmetic operation is fed back to the step 304 at the step312, then the processes from the step 304 to the step 311 may beiteratively performed until the MAC arithmetic operation is performedfor all of the rows of the weight matrix with the vector matrix. If theMAC arithmetic operation for the eighth row of the weight matrixterminates and the row number of the weight matrix changes from ‘8’ to‘9’ at the step 311, the MAC arithmetic operation may terminate becausethe row number of ‘9’ is greater than the last row number of ‘8’ at thestep 312.

FIG. 14 illustrates another example of a MAC arithmetic operationperformed in the PIM system 1-1 according to the first embodiment of thepresent disclosure. As illustrated in FIG. 14 , the MAC arithmeticoperation performed by the PIM system 1-1 may further include an addingcalculation of the MAC result matrix and a bias matrix. Specifically, asdescribed with reference to FIG. 5 , the PIM device 100 may execute thematrix multiplying calculation of the ‘8×8’ weight matrix and the ‘8×1’vector matrix according to control of the PIM controller 200. As aresult of the matrix multiplying calculation of the ‘8×8’ weight matrixand the ‘8×1’ vector matrix, the ‘8×1’ MAC result matrix having theeight elements MAC0.0, . . . , and MAC7.0 may be generated. The ‘8×1’MAC result matrix may be added to a ‘8×1’ bias matrix. The ‘8×1’ biasmatrix may have elements B0.0, . . . , and B7.0 corresponding to biasdata. The bias data may be set to reduce an error of the MAC resultmatrix. As a result of the adding calculation of the MAC result matrixand the bias matrix, a ‘8×1’ biased result matrix having eight elementsY0.0, . . . , and Y7.0 may be generated.

FIG. 15 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 14 in the PIM system 1-1according to the first embodiment of the present disclosure. Moreover,FIG. 16 illustrates an example of a configuration of a MAC operator120-1 for performing the MAC arithmetic operation of FIG. 14 in the PIMsystem 1-1 according to the first embodiment of the present disclosure.In FIG. 16 , the same reference numerals or the same reference symbolsas used in FIG. 4 denote the same elements, and the detaileddescriptions of the same elements as indicated in the previousembodiment will be omitted hereinafter. Referring to FIG. 15 , the firstdata (i.e., the weight data) may be written into the first memory bank111 at a step 321 to perform the MAC arithmetic operation in the PIMdevice 100. Thus, the weight data may be stored in the first memory bank111 of the PIM device 100. In the present embodiment, it may be assumedthat the weight data are the elements W0.0, . . . , and W7.7constituting the weight matrix of FIG. 14 .

At a step 322, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-1 to the PIM controller 200 of thePIM system 1-1. In an embodiment, if no inference request signal istransmitted to the PIM controller 200, the PIM system 1-1 may be in astandby mode until the inference request signal is transmitted to thePIM controller 200. Alternatively, if no inference request signal istransmitted to the PIM controller 200, the PIM system 1-1 may performoperations (e.g., data read/write operations) other than the MACarithmetic operation in the memory mode until the inference requestsignal is transmitted to the PIM controller 200. In the presentembodiment, it may be assumed that the second data (i.e., the vectordata) are transmitted together with the inference request signal. Inaddition, it may be assumed that the vector data are the elements X0.0,. . . , and X7.0 constituting the vector matrix of FIG. 14 . If theinference request signal is transmitted to the PIM controller 200 at thestep 322, the PIM controller 200 may write the vector data transmittedwith the inference request signal into the second memory bank 112 at astep 323. Accordingly, the vector data may be stored in the secondmemory bank 112 of the PIM device 100.

At a step 324, the output latch of the MAC operator may be initially setto have the bias data and the initially set bias data may be fed back toan accumulative adder of the MAC operator. This process is executed toperform the matrix adding calculation of the MAC result matrix and thebias matrix, which is described with reference to FIG. 14 . In otherwords, the output latch 123-1 in the data output circuit 123-A of theMAC operator (120-1) is set to have the bias data. Because the matrixmultiplying calculation is executed for the first row of the weightmatrix, the output latch 123-1 may be initially set to have the elementB0.0 located at a cross point of the first row and the first column ofthe bias matrix as the bias data. The output latch 123-1 may output thebias data B0.0, and the bias data B0.0 outputted from the output latch123-1 may be inputted to the accumulative adder 122-21D of the additionlogic circuit 122-2, as illustrated in FIG. 16 .

In an embodiment, in order to output the bias data B0.0 out of theoutput latch 123-1 and to feed back the bias data B0.0 to theaccumulative adder 122-21D, the MAC command generator 240 of the PIMcontroller 200 may transmit the MAC output latch signal MAC_L3 to theMAC operator 120-1 of the PIM device 100. When a subsequent MACarithmetic operation is performed, the accumulative adder 122-21D of theMAC operator 120-1 may add the MAC result data MAC0.0 outputted from theadder 122-21C disposed at the last stage to the bias data B0.0 which isfed back from the output latch 123-1 to generate the biased result dataY0.0 and may output the biased result data Y0.0 to the output latch123-1. The biased result data Y0.0 may be outputted from the outputlatch 123-1 in synchronization with the MAC output latch signal MAC_L3transmitted in a subsequent process.

In a step 325, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC read signal MAC_RD_BK0 to thePIM device 100. In addition, the address generator 250 of the PIMcontroller 200 may generate and transmit the bank selection signal BSand the row/column address ADDR_R/ADDR_C to the PIM device 100. The step325 may be executed in the same way as described with reference to FIG.7 . In a step 326, the MAC command generator 240 of the PIM controller200 may generate and transmit the second MAC read signal MAC_RD_BK1 tothe PIM device 100. In addition, the address generator 250 of the PIMcontroller 200 may generate and transmit the bank selection signal BSfor selecting the second memory bank 112 and the row/column addressADDR_R/ADDR_C to the PIM device 100. The step 326 may be executed in thesame way as described with reference to FIG. 8 .

At a step 327, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC input latch signal MAC_L1 to thePIM device 100. The step 327 may be executed in the same way asdescribed with reference to FIG. 9 . The first MAC input latch signalMAC_L1 may control the input latch operation of the first data for theMAC operator 120 of the PIM device 100. The input latch operation of thefirst data may be performed in the same way as described with referenceto FIG. 11 . At a step 328, the MAC command generator 240 of the PIMcontroller 200 may generate and transmit the second MAC input latchsignal MAC_L2 to the PIM device 100. The step 328 may be executed in thesame way as described with reference to FIG. 10 . The second MAC inputlatch signal MAC_L2 may control the input latch operation of the seconddata for the MAC operator 120 of the PIM device 100. The input latchoperation of the second data may be performed in the same way asdescribed with reference to FIG. 11 .

At a step 329, the MAC circuit 122 of the MAC operator 120 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. Specifically,each of the multipliers 122-11 of the multiplication logic circuit 122-1may perform a multiplying calculation of the inputted data, and theresult data of the multiplying calculation may be inputted to theaddition logic circuit 122-2. The addition logic circuit 122-2 mayinclude the four adders 122-21A disposed at the first stage, the twoadders 122-21B disposed at the second stage, the adder 122-21C disposedat the third stage, and the accumulative adder 122-21D, as illustratedin FIG. 16 . The accumulative adder 122-21D may add output data of theadder 122-21C to feedback data fed back from the output latch 123-1 tooutput the result of the adding calculation. The output data of theadder 122-21C may be the matrix multiplying result MAC0.0, whichcorresponds to the result of the matrix multiplying calculation of thefirst row of the weight matrix and the first column of the vectormatrix. The accumulative adder 122-21D may add the output data MAC0.0 ofthe adder 122-21C to the bias data B0.0 fed back from the output latch123-1 to output the result of the adding calculation. The output dataY0.0 of the accumulative adder 122-21D may be inputted to the outputlatch 123 disposed in a data output circuit 123-A of the MAC operator120-1.

At a step 330, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 100. The step 330 may be executed in the same way as describedwith reference to FIG. 12 . The MAC output latch signal MAC_L3 maycontrol the output latch operation of the MAC result data MAC0.0, whichis performed by the MAC operator 120-1 of the PIM device 100. The biasedresult data Y0.0 transmitted from the MAC circuit 122 of the MACoperator 120 to the output latch 123-1 may be outputted from the outputlatch 123-1 in synchronization with the MAC output latch signal MAC_L3.The biased result data Y0.0 outputted from the output latch 123 may beinputted to the transfer gate 123-2.

At a step 331, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 100. The step 331 may be executed in the same way asdescribed with reference to FIG. 13 . The MAC latch reset signalMAC_L_RST may control an output operation of the biased result data Y0.0generated by the MAC operator 120 and a reset operation of the outputlatch 123-1 included in the MAC operator 120. The transfer gate 123-2receiving the biased result data Y0.0 from the output latch 123-1 of thedata output circuit 123-A included in the MAC operator 120 may besynchronized with the MAC latch reset signal MAC_L_RST to output thebiased result data Y0.0. In an embodiment, the biased result data Y0.0outputted from the MAC operator 120 may be stored into the first memorybank 111 or the second memory bank 112 through the first BIO line or thesecond BIO line in the PIM device 100.

At a step 332, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed during the previous steps, therow number of the weight matrix may change from ‘1’ to ‘2’ at the step332. At a step 333, whether the row number changed at the step 332 isgreater than the row number of the last row (i.e., the eighth row of thecurrent example) of the weight matrix may be determined. Because the rownumber of the weight matrix is changed to ‘2’ at the step 332, a processof the MAC arithmetic operation may be fed back to the step 324.

If the process of the MAC arithmetic operation is fed back to the step324 from the step 333, then the same processes as described withreference to the steps 324 to 331 may be executed again for theincreased row number of the weight matrix. That is, as the row number ofthe weight matrix changes from ‘1’ to ‘2’, the MAC arithmetic operationmay be performed for the second row of the weight matrix instead of thefirst row of the weight matrix with the vector matrix and the bias dataB0.0 in the output latch 123-1 initially set at the step 324 may bechanged into the bias data B1.0. If the process of the MAC arithmeticoperation is fed back to the step 324 at the step 333, the processesfrom the step 324 to the step 332 may be iteratively performed until theMAC arithmetic operation is performed for all of the rows of the weightmatrix with the vector matrix. If the MAC arithmetic operation for theeighth row of the weight matrix terminates and the row number of theweight matrix changes from ‘8’ to ‘9’ at the step 332, the MACarithmetic operation may terminate because the row number of ‘9’ isgreater than the last row number of ‘8’ at the step 333.

FIG. 17 illustrates yet another example of a MAC arithmetic operationperformed in the PIM system 1-1 according to the first embodiment of thepresent disclosure. As illustrated in FIG. 17 , the MAC arithmeticoperation performed by the PIM system 1-1 may further include a processfor applying the biased result matrix to an activation function.Specifically, as described with reference to FIG. 14 , the PIM device100 may execute the matrix multiplying calculation of the ‘8×8’ weightmatrix and the ‘8×1’ vector matrix according to control of the PIMcontroller 200 to generate the MAC result matrix. In addition, the MACresult matrix may be added to the bias matrix to generate biased resultmatrix.

The biased result matrix may be applied to the activation function. Theactivation function means a function which is used to calculate a uniqueoutput value by comparing a MAC calculation value with a critical valuein an MLP-type neural network. In an embodiment, the activation functionmay be a unipolar activation function which generates only positiveoutput values or a bipolar activation function which generates negativeoutput values as well as positive output values. In differentembodiments, the activation function may include a sigmoid function, ahyperbolic tangent (Tan h) function, a rectified linear unit (ReLU)function, a leaky ReLU function, an identity function, and a maxoutfunction.

FIG. 18 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 17 in the PIM system 1-1according to the first embodiment of the present disclosure. Moreover,FIG. 19 illustrates an example of a configuration of a MAC operator120-2 for performing the MAC arithmetic operation of FIG. 17 in the PIMsystem 1-1 according to the first embodiment of the present disclosure.In FIG. 19 , the same reference numerals or the same reference symbolsas used in FIG. 4 denote the same elements, and the detaileddescriptions of the same elements as mentioned in the previousembodiment will be omitted hereinafter. Referring to FIG. 18 , the firstdata (i.e., the weight data) may be written into the first memory bank111 at a step 341 to perform the MAC arithmetic operation in the PIMdevice 100. Thus, the weight data may be stored in the first memory bank111 of the PIM device 100. In the present embodiment, it may be assumedthat the weight data are the elements W0.0, . . . , and W7.7constituting the weight matrix of FIG. 17 .

At a step 342, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-1 to the PIM controller 200 of thePIM system 1-1. In an embodiment, if no inference request signal istransmitted to the PIM controller 200, the PIM system 1-1 may be in astandby mode until the inference request signal is transmitted to thePIM controller 200. Alternatively, if no inference request signal istransmitted to the PIM controller 200, the PIM system 1-1 may performoperations (e.g., the data read/write operations) other than the MACarithmetic operation in the memory mode until the inference requestsignal is transmitted to the PIM controller 200. In the presentembodiment, it may be assumed that the second data (i.e., the vectordata) are transmitted together with the inference request signal. Inaddition, it may be assumed that the vector data are the elements X0.0,. . . , and X7.0 constituting the vector matrix of FIG. 17 . If theinference request signal is transmitted to the PIM controller 200 at thestep 342, then the PIM controller 200 may write the vector datatransmitted with the inference request signal into the second memorybank 112 at a step 343. Accordingly, the vector data may be stored inthe second memory bank 112 of the PIM device 100.

At a step 344, an output latch of a MAC operator may be initially set tohave bias data and the initially set bias data may be fed back to anaccumulative adder of the MAC operator. This process is executed toperform the matrix adding calculation of the MAC result matrix and thebias matrix, which is described with reference to FIG. 17 . That is, asillustrated in FIG. 19 , the output latch 123-1 of the MAC operator(120-2 of FIG. 19 ) may be initially set to have the bias data of thebias matrix. Because the matrix multiplying calculation is executed forthe first row of the weight matrix, the element B0.0 located at firstrow and the first column of the bias matrix may be initially set as thebias data in the output latch 123-1. The output latch 123-1 may outputthe bias data B0.0, and the bias data B0.0 outputted from the outputlatch 123-1 may be inputted to the accumulative adder 122-21D of the MACoperator 120-2.

In an embodiment, in order to output the bias data B0.0 out of theoutput latch 123-1 and to feed back the bias data B0.0 to theaccumulative adder 122-21D, the MAC command generator 240 of the PIMcontroller 200 may transmit the MAC output latch signal MAC_L3 to theMAC operator 120-2 of the PIM device 100. When a subsequent MACarithmetic operation is performed, the accumulative adder 122-21D of theMAC operator 120-2 may add the MAC result data MAC0.0 outputted from theadder 122-21C disposed at the last stage to the bias data B0.0 which isfed back from the output latch 123-1 to generate the biased result dataY0.0 and may output the biased result data Y0.0 to the output latch123-1. As illustrated in FIG. 19 , the biased result data Y0.0 may betransmitted from the output latch 123-1 to an activation function logiccircuit 123-5 disposed in a data output circuit 123-B of the MACoperator 120-2 in synchronization with the MAC output latch signalMAC_L3 transmitted in a subsequent process.

In a step 345, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC read signal MAC_RD_BK0 to thePIM device 100. In addition, the address generator 250 of the PIMcontroller 200 may generate and transmit the bank selection signal BSand the row/column address ADDR_R/ADDR_C to the PIM device 100. The step345 may be executed in the same way as described with reference to FIG.7 . In a step 346, the MAC command generator 240 of the PIM controller200 may generate and transmit the second MAC read signal MAC_RD_BK1 tothe PIM device 100. In addition, the address generator 250 of the PIMcontroller 200 may generate and transmit the bank selection signal BSfor selecting the second memory bank 112 and the row/column addressADDR_R/ADDR_C to the PIM device 100. The step 346 may be executed in thesame way as described with reference to FIG. 8 .

At a step 347, the MAC command generator 240 of the PIM controller 200may generate and transmit the first MAC input latch signal MAC_L1 to thePIM device 100. The step 347 may be executed in the same way asdescribed with reference to FIG. 9 . The first MAC input latch signalMAC_L1 may control the input latch operation of the first data for theMAC operator 120 of the PIM device 100. The input latch operation of thefirst data may be performed in the same way as described with referenceto FIG. 11 . At a step 348, the MAC command generator 240 of the PIMcontroller 200 may generate and transmit the second MAC input latchsignal MAC_L2 to the PIM device 100. The step 348 may be executed in thesame way as described with reference to FIG. 10 . The second MAC inputlatch signal MAC_L2 may control the input latch operation of the seconddata for the MAC operator 120 of the PIM device 100. The input latchoperation of the second data may be performed in the same way asdescribed with reference to FIG. 11 .

At a step 349, the MAC circuit 122 of the MAC operator 120 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. Specifically,each of the multipliers 122-11 of the multiplication logic circuit 122-1may perform a multiplying calculation of the inputted data, and theresult data of the multiplying calculation may be inputted to theaddition logic circuit 122-2. The addition logic circuit 122-2 mayinclude the four adders 122-21A disposed at the first stage, the twoadders 122-21B disposed at the second stage, the adder 122-21C disposedat the third stage, and the accumulative adder 122-21D, as illustratedin FIG. 19 . The accumulative adder 122-21D may add output data of theadder 122-21C to feedback data fed back from the output latch 123-1 tooutput the result of the adding calculation. The output data of theadder 122-21C may be the element MAC0.0 of the ‘8×1’ MAC result matrix,which corresponds to the result of the matrix multiplying calculation ofthe first row of the weight matrix and the first column of the vectormatrix. The accumulative adder 122-21D may add the output data MAC0.0 ofthe adder 122-21C to the bias data B0.0 fed back from the output latch123-1 to output the result of the adding calculation. The output dataY0.0 of the accumulative adder 122-21D may be inputted to the outputlatch 123-1 disposed in the data output circuit 123-A of the MACoperator 120.

At a step 350, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 100. The step 350 may be executed in the same way as describedwith reference to FIG. 12 . The MAC output latch signal MAC_L3 maycontrol the output latch operation of the output latch 123-1 included inthe MAC operator 120 of the PIM device 100. The biased result data Y0.0transmitted from the MAC circuit 122 of the MAC operator 120 to theoutput latch 123-1 may be outputted from the output latch 123-1 insynchronization with the MAC output latch signal MAC_L3. The biasedresult data Y0.0 outputted from the output latch 123-1 may be inputtedto the activation function logic circuit 123-5. At a step 351, theactivation function logic circuit 123-5 may apply an activation functionto the biased result data Y0.0 to generate a final output value, and thefinal output value may be inputted to the transfer gate (123-2 of FIG. 4). This, for example, is the final output value for the current of Rwhich is incremented in step 354.

At a step 352, the MAC command generator 240 of the PIM controller 200may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 100. The step 352 may be executed in the same way asdescribed with reference to FIG. 13 . The MAC latch reset signalMAC_L_RST may control an output operation of the final output valuegenerated by the MAC operator 120 and a reset operation of the outputlatch 123-1 included in the MAC operator 120. The transfer gate 123-2receiving the final output value from the activation function logiccircuit 123-5 of the data output circuit 123-B included in the MACoperator 120 may be synchronized with the MAC latch reset signalMAC_L_RST to output the final output value. In an embodiment, the finaloutput value outputted from the MAC operator 120 may be stored into thefirst memory bank 111 or the second memory bank 112 through the firstBIO line or the second BIO line in the PIM device 100.

At a step 353, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed during the previous steps, therow number of the weight matrix may change from ‘1’ to ‘2’ at the step353. At a step 354, whether the row number changed at the step 353 isgreater than the row number of the last row (i.e., the eighth row) ofthe weight matrix may be determined. Because the row number of theweight matrix is changed to ‘2’ at the step 353, a process of the MACarithmetic operation may be fed back to the step 344.

If the process of the MAC arithmetic operation is fed back to the step344 from the step 354, the same processes as described with reference tothe steps 344 to 354 may be executed again for the increased row numberof the weight matrix. That is, as the row number of the weight matrixchanges from ‘1’ to ‘2’, the MAC arithmetic operation may be performedfor the second row of the weight matrix instead of the first row of theweight matrix with the vector matrix, and the bias data B0.0 in theoutput latch 123-1 initially set at the step 344 may be changed to thebias data B1.0. If the process of the MAC arithmetic operation is fedback to the step 344 from the step 354, the processes from the step 344to the step 354 may be iteratively performed until the MAC arithmeticoperation is performed for all of the rows of the weight matrix with thevector matrix. For an embodiment, a plurality of final output values,namely, one final output value for each incremented value of R,represents an ‘N×1’ final result matrix. If the MAC arithmetic operationfor the eighth row of the weight matrix terminates and the row number ofthe weight matrix changes from ‘8’ to ‘9’ at the step 354, the MACarithmetic operation may terminate because the row number of ‘9’ isgreater than the last row number of ‘8’ at the step 354.

FIG. 20 is a block diagram illustrating a PIM system 1-2 according to asecond embodiment of the present disclosure. In FIG. 20 , the samereference numerals or the same reference symbols as used in FIG. 2denote the same elements. As illustrated in FIG. 20 , the PIM system 1-2may be configured to include a PIM device 400 and a PIM controller 500.The PIM device 400 may be configured to include a memory bank (BANK) 411corresponding to a storage region, a global buffer 412, a MAC operator420, an interface (I/F) 431, and a data input/output (I/O) pad 432. Foran embodiment, the MAC operator 420 represents a MAC operator circuit.The memory bank (BANK) 411 and the MAC operator 420 included in the PIMdevice 400 may constitute one MAC unit. In another embodiment, the PIMdevice 400 may include a plurality of MAC units. The memory bank (BANK)411 may represent a memory region for storing data, for example, a DRAMdevice. The global buffer 412 may also represent a memory region forstoring data, for example, a DRAM device or an SRAM device. The memorybank (BANK) 411 may be a component unit which is independently activatedand may be configured to have the same data bus width as data I/O linesin the PIM device 400. In an embodiment, the memory bank 411 may operatethrough interleaving such that an active operation of the memory bank411 is performed in parallel while another memory bank is selected. Thememory bank 411 may include at least one cell array which includesmemory unit cells located at cross points of a plurality of rows and aplurality of columns.

Although not shown in the drawings, a core circuit may be disposedadjacent to the memory bank 411. The core circuit may include X-decodersXDECs and Y-decoders/IO circuits YDEC/IOs. An X-decoder XDEC may also bereferred to as a word line decoder or a row decoder. The X-decoder XDECmay receive a row address ADDR_R from the PIM controller 500 and maydecode the row address ADDR_R to select and enable one of the rows(i.e., word lines) coupled to the selected memory bank. Each of theY-decoders/IO circuits YDEC/IOs may include a Y-decoder YDEC and an I/Ocircuit JO. The Y-decoder YDEC may also be referred to as a bit linedecoder or a column decoder. The Y-decoder YDEC may receive a columnaddress ADD_C from the PIM controller 500 and may decode the columnaddress ADD_C to select and enable at least one of the columns (i.e.,bit lines) coupled to the selected memory bank. Each of the I/O circuitsmay include an I/O sense amplifier for sensing and amplifying a level ofa read datum outputted from the corresponding memory bank during a readoperation for the memory bank 411. In addition, the I/O circuit mayinclude a write driver for driving a write datum during a writeoperation for the memory bank 411.

The MAC operator 420 of the PIM device 400 may have mostly the sameconfiguration as the MAC operator 120 described with reference to FIG. 4. That is, the MAC operator 420 may be configured to include the datainput circuit 121, the MAC circuit 122, and the data output circuit 123,as described with reference to FIG. 4 . The data input circuit 121 maybe configured to include the first input latch 121-1 and the secondinput latch 121-2. The MAC circuit 122 may be configured to include themultiplication logic circuit 122-1 and the addition logic circuit 122-2.The data output circuit 123 may be configured to include the outputlatch 123-1, the transfer gate 123-2, the delay circuit 123-3, and theinverter 123-4. In an embodiment, the first input latch 121-1, thesecond input latch 121-2, and the output latch 123-1 may be realizedusing flip-flops.

The MAC operator 420 may be different from the MAC operator 120 in thata MAC input latch signal MAC_L1 is simultaneously inputted to both ofclock terminals of the first and second input latches 121-1 and 121-2.As indicated in the following descriptions, the weight data and thevector data may be simultaneously transmitted to the MAC operator 420 ofthe PIM device 400 included in the PIM system 1-2 according to thepresent embodiment. That is, the first data DA1 (i.e., the weight data)and the second data DA2 (i.e., the vector data) may be simultaneouslyinputted to both of the first input latch 121-1 and the second inputlatch 121-2 constituting the data input circuit 121, respectively.Accordingly, it may be unnecessary to apply an extra control signal tothe clock terminals of the first and second input latches 121-1 and121-2, and thus the MAC input latch signal MAC_L1 may be simultaneouslyinputted to both of the clock terminals of the first and second inputlatches 121-1 and 121-2 included in the MAC operator 420.

In another embodiment, the MAC operator 420 may be realized to have thesame configuration as the MAC operator 120-1 described with reference toFIG. 16 to perform the operation illustrated in FIG. 14 . Even in such acase, the MAC operator 420 may have the same configuration as describedwith reference to FIG. 16 except that the MAC input latch signal MAC_L1is simultaneously inputted to both of the clock terminals of the firstand second input latches 121-1 and 121-2 constituting the data inputcircuit 121. In yet another embodiment, the MAC operator 420 may berealized to have the same configuration as the MAC operator 120-2described with reference to FIG. 19 to perform the operation illustratedin FIG. 17 . Even in such a case, the MAC operator 420 may have the sameconfiguration as described with reference to FIG. 19 except that the MACinput latch signal MAC_L1 is simultaneously inputted to both of theclock terminals of the first and second input latches 121-1 and 121-2constituting the data input circuit 121.

The interface 431 of the PIM device 400 may receive the memory commandM_CMD, the MAC commands MAC_CMDs, the bank selection signal BS, and therow/column addresses ADDR_R/ADDR_C from the PIM controller 500. Theinterface 431 may output the memory command M_CMD, together with thebank selection signal BS and the row/column addresses ADDR_R/ADDR_C, tothe memory bank 411. The interface 431 may output the MAC commandsMAC_CMDs to the memory bank 411 and the MAC operator 420. In such acase, the interface 431 may output the bank selection signal BS and therow/column addresses ADDR_R/ADDR_C to the memory bank 411. The data I/Opad 432 of the PIM device 400 may function as a data communicationterminal between a device external to the PIM device 400, the globalbuffer 412, and the MAC unit (which includes the memory bank 411 and theMAC operator 420) included in the PIM device 400. The external device tothe PIM device 400 may correspond to the PIM controller 500 of the PIMsystem 1-2 or a host located outside the PIM system 1-2. Accordingly,data outputted from the host or the PIM controller 500 may be inputtedinto the PIM device 400 through the data I/O pad 432. In addition, datagenerated by the PIM device 400 may be transmitted to the externaldevice to the PIM device 400 through the data I/O pad 432.

The PIM controller 500 may control operations of the PIM device 400. Inan embodiment, the PIM controller 500 may control the PIM device 400such that the PIM device 400 operates in the memory mode or the MACmode. In the event that the PIM controller 500 controls the PIM device500 such that the PIM device 400 operates in the memory mode, the PIMdevice 400 may perform a data read operation or a data write operationfor the memory bank 411. In the event that the PIM controller 500controls the PIM device 400 such that the PIM device 400 operates in theMAC mode, the PIM device 400 may perform the MAC arithmetic operationfor the MAC operator 420. In the event that the PIM controller 500controls the PIM device 400 such that the PIM device 400 operates in theMAC mode, the PIM device 400 may also perform the data read operationand the data write operation for the memory bank 411 and the globalbuffer 412 to execute the MAC arithmetic operation.

The PIM controller 500 may be configured to include the command queuelogic 210, the scheduler 220, the memory command generator 230, a MACcommand generator 540, and an address generator 550. The scheduler 220may include the mode selector 221. The command queue logic 210 mayreceive the request REQ from an external device (e.g., a host of the PIMsystem 1-2) and store a command queue corresponding the request REQ inthe command queue logic 210. The command queue stored in the commandqueue logic 210 may be transmitted to the memory command generator 230or the MAC command generator 540 according to a sequence determined bythe scheduler 220. The scheduler 220 may adjust a timing of the commandqueue when the command queue stored in the command queue logic 210 isoutputted from the command queue logic 210. The scheduler 210 mayinclude the mode selector 221 that generates a mode selection signalincluding information on whether command queue stored in the commandqueue logic 210 relates to the memory mode or the MAC mode. The memorycommand generator 230 may receive the command queue related to thememory mode of the PIM device 400 from the command queue logic 210 togenerate and output the memory command M_CMD. The command queue logic210, the scheduler 220, the mode selector 221, and the memory commandgenerator 230 may have the same function as described with reference toFIG. 2 .

The MAC command generator 540 may receive the command queue related tothe MAC mode of the PIM device 400 from the command queue logic 210. TheMAC command generator 540 may decode the command queue to generate andoutput the MAC commands MAC_CMDs. The MAC commands MAC_CMDs outputtedfrom the MAC command generator 540 may be transmitted to the PIM device400. The data read operation for the memory bank 411 of the PIM device400 may be performed by the MAC commands MAC_CMDs outputted from the MACcommand generator 540, and the MAC arithmetic operation of the MACoperator 420 may also be performed by the MAC commands MAC_CMDsoutputted from the MAC command generator 540. The MAC commands MAC_CMDsand the MAC arithmetic operation of the PIM device 400 according to theMAC commands MAC_CMDs will be described in detail with reference to FIG.21 .

The address generator 550 may receive address information from thecommand queue logic 210. The address generator 550 may generate the bankselection signal BS for selecting a memory bank where, for example, thememory bank 411 represents multiple memory banks. The address generator550 may transmit the bank selection signal BS to the PIM device 400. Inaddition, the address generator 550 may generate the row address ADDR_Rand the column address ADDR_C for accessing a region (e.g., memorycells) in the memory bank 411 and may transmit the row address ADDR_Rand the column address ADDR_C to the PIM device 400.

FIG. 21 illustrates the MAC commands MAC_CMDs outputted from the MACcommand generator 540 included in the PIM system 1-2 according to thesecond embodiment of the present disclosure. As illustrated in FIG. 21 ,the MAC commands MAC_CMDs may include first to fourth MAC commandsignals. In an embodiment, the first MAC command signal may be a MACread signal MAC_RD_BK, the second MAC command signal may be a MAC inputlatch signal MAC_L1, the third MAC command signal may be a MAC outputlatch signal MAC_L3, and the fourth MAC command signal may be a MAClatch reset signal MAC_L_RST.

The MAC read signal MAC_RD_BK may control an operation for reading thefirst data (e.g., the weight data) out of the memory bank 411 totransmit the first data to the MAC operator 420. The MAC input latchsignal MAC_L1 may control an input latch operation of the weight datatransmitted from the first memory bank 411 to the MAC operator 420. TheMAC output latch signal MAC_L3 may control an output latch operation ofthe MAC result data generated by the MAC operator 420. And, the MAClatch reset signal MAC_L_RST may control an output operation of the MACresult data generated by the MAC operator 420 and a reset operation ofan output latch included in the MAC operator 420.

The PIM system 1-2 according to the present embodiment may also beconfigured to perform the deterministic MAC arithmetic operation. Thus,the MAC commands MAC_CMDs transmitted from the PIM controller 500 to thePIM device 400 may be sequentially generated with fixed time intervals.Accordingly, the PIM controller 500 does not require any extra endsignals of various operations executed for the MAC arithmetic operationto generate the MAC commands MAC_CMDs for controlling the MAC arithmeticoperation. In an embodiment, latencies of the various operationsexecuted by MAC commands MAC_CMDs for controlling the MAC arithmeticoperation may be set to have fixed values in order to perform thedeterministic MAC arithmetic operation. In such a case, the MAC commandsMAC_CMDs may be sequentially outputted from the PIM controller 500 withfixed time intervals corresponding to the fixed latencies.

FIG. 22 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 5 , which are performed inthe PIM system 1-2 according to the second embodiment of the presentdisclosure. In addition, FIGS. 23 to 26 are block diagrams illustratingthe processes of the MAC arithmetic operation illustrated in FIG. 5 ,which are performed in the PIM system 1-2 according to the secondembodiment of the present disclosure. Referring to FIGS. 22 to 26 , thefirst data (i.e., the weight data) may be written into the memory bank411 at a step 361 to perform the MAC arithmetic operation. Thus, theweight data may be stored in the memory bank 411 of the PIM device 400.In the present embodiment, it may be assumed that the weight data arethe elements W0.0, . . . , and W7.7 constituting the weight matrix ofFIG. 5 .

At a step 362, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-2 to the PIM controller 500 of thePIM system 1-2. In an embodiment, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may be in astandby mode until the inference request signal is transmitted to thePIM controller 500. Alternatively, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may performoperations (e.g., data read/write operations) other than the MACarithmetic operation in the memory mode until the inference requestsignal is transmitted to the PIM controller 500. In the presentembodiment, it may be assumed that the second data (i.e., the vectordata) are transmitted together with the inference request signal. Inaddition, it may be assumed that the vector data are the elements X0.0,. . . , and X7.0 constituting the vector matrix of FIG. 5 . If theinference request signal is transmitted to the PIM controller 500 at thestep 362, then the PIM controller 500 may write the vector datatransmitted with the inference request signal into the global buffer 412at a step 363. Accordingly, the vector data may be stored in the globalbuffer 412 of the PIM device 400.

At a step 364, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC read signal MAC_RD_BK to the PIMdevice 400, as illustrated in FIG. 23 . In such a case, the addressgenerator 550 of the PIM controller 500 may generate and transmit therow/column address ADDR_R/ADDR_C to the PIM device 400. Although notshown in the drawings, if a plurality of memory banks are disposed inthe PIM device 400, the address generator 550 may transmit a bankselection signal for selecting the memory bank 411 among the pluralityof memory banks as well as the row/column address ADDR_R/ADDR_C to thePIM device 400. The MAC read signal MAC_RD_BK inputted to the PIM device400 may control the data read operation for the memory bank 411 of thePIM device 400. The memory bank 411 may output and transmit the elementsW0.0, . . . , and W0.7 in the first row of the weight matrix of theweight data stored in a region of the memory bank 411, which isdesignated by the row/column address ADDR_R/ADDR_C, to the MAC operator420 in response to the MAC read signal MAC_RD_BK. In an embodiment, thedata transmission from the memory bank 411 to the MAC operator 420 maybe executed through a BIO line which is provided specifically for datatransmission between the memory bank 411 and the MAC operator 420.

Meanwhile, the vector data X0.0, . . . , and X7.0 stored in the globalbuffer 412 may also be transmitted to the MAC operator 420 insynchronization with a point in time when the weight data aretransmitted from the memory bank 411 to the MAC operator 420. In orderto transmit the vector data X0.0, . . . , and X7.0 from the globalbuffer 412 to the MAC operator 420, a control signal for controlling theread operation for the global buffer 412 may be generated insynchronization with the MAC read signal MAC_RD_BK outputted from theMAC command generator 540 of the PIM controller 500. The datatransmission between the global buffer 412 and the MAC operator 420 maybe executed through a GIO line. Thus, the weight data and the vectordata may be independently transmitted to the MAC operator 420 throughtwo separate transmission lines, respectively. In an embodiment, theweight data and the vector data may be simultaneously transmitted to theMAC operator 420 through the BIO line and the GIO line, respectively.

At a step 365, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC input latch signal MAC_L1 to the PIMdevice 400, as illustrated in FIG. 24 . The MAC input latch signalMAC_L1 may control the input latch operation of the weight data and thevector data for the MAC operator 420 of the PIM device 400. The elementsW0.0, . . . , and W0.7 in the first row of the weight matrix and theelements X0.0, . . . , and X7.0 in the first column of the vector matrixmay be inputted to the MAC circuit 122 of the MAC operator 420 by theinput latch operation. The MAC circuit 122 may include the plurality ofmultipliers (e.g., the eight multipliers 122-11), the number of which isequal to the number of columns of the weight matrix and the number ofrows of the vector matrix. The elements W0.0, . . . , and W0.7 in thefirst row of the weight matrix may be inputted to the first to eighthmultipliers 122-11, respectively, and the elements X0.0, . . . , andX7.0 in the first column of the vector matrix may also be inputted tothe first to eighth multipliers 122-11, respectively.

At a step 366, the MAC circuit 122 of the MAC operator 420 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. Specifically,as described with reference to FIG. 4 , each of the multipliers 122-11of the multiplication logic circuit 122-1 may perform a multiplyingcalculation of the inputted data, and the result data of the multiplyingcalculation may be inputted to the addition logic circuit 122-2. Theaddition logic circuit 122-2 may receive output data from themultipliers 122-11 and may perform the adding calculation of the outputdata of the multipliers 122-11 to output the result data of the addingcalculation. The output data of the addition logic circuit 122-2 maycorrespond to result data (i.e., MAC result data) of the MAC arithmeticoperation of the first row included in the weight matrix and the columnincluded in the vector matrix. Thus, the output data of the additionlogic circuit 122-2 may correspond to the element MAC0.0 located at thefirst row of the ‘8×1’ MAC result matrix having the eight elements ofMAC0.0, . . . , and MAC7.0 illustrated in FIG. 5 . The output dataMAC0.0 of the addition logic circuit 122-2 may be inputted to the outputlatch 123-1 disposed in the data output circuit 123 of the MAC operator420, as described with reference to FIG. 4 .

At a step 367, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 400, as illustrated in FIG. 25 . The MAC output latch signalMAC_L3 may control the output latch operation of the MAC result dataMAC0.0 performed by the MAC operator 420 of the PIM device 400. The MACresult data MAC0.0 transmitted from the MAC circuit 122 of the MACoperator 420 to the output latch 123-1 may be outputted from the outputlatch 123-1 by the output latch operation performed in synchronizationwith the MAC output latch signal MAC_L3, as described with reference toFIG. 4 . The MAC result data MAC0.0 outputted from the output latch123-1 may be inputted to the transfer gate 123-2 of the data outputcircuit 123.

At a step 368, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 400, as illustrated in FIG. 26 . The MAC latch reset signalMAC_L_RST may control an output operation of the MAC result data MAC0.0generated by the MAC operator 420 and a reset operation of the outputlatch 123-1 included in the MAC operator 420. As described withreference to FIG. 4 , the transfer gate 123-2 receiving the MAC resultdata MAC0.0 from the output latch 123-1 of the MAC operator 420 may besynchronized with the MAC latch reset signal MAC_L_RST to output the MACresult data MAC0.0. In an embodiment, the MAC result data MAC0.0outputted from the MAC operator 420 may be stored into the memory bank411 through the BIO line in the PIM device 400.

At a step 369, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed during the previous steps, therow number of the weight matrix may change from ‘1’ to ‘2’ at the step369. At a step 370, whether the row number changed at the step 369 isgreater than the row number of the last row (i.e., the eighth row) ofthe weight matrix may be determined. Because the row number of theweight matrix is changed to ‘2’ at the step 370, a process of the MACarithmetic operation may be fed back to the step 364.

If the process of the MAC arithmetic operation is fed back to the step364 from the step 370, the same processes as described with reference tothe steps 364 to 370 may be executed again for the increased row numberof the weight matrix. That is, as the row number of the weight matrixchanges from ‘1’ to ‘2’, the MAC arithmetic operation may be performedfor the second row of the weight matrix instead of the first row of theweight matrix with the vector matrix. If the process of the MACarithmetic operation is fed back to the step 364 from the step 370, theprocesses from the step 364 to the step 370 may be iteratively performeduntil the MAC arithmetic operation is performed for all of the rows ofthe weight matrix with the vector matrix. If the MAC arithmeticoperation for the eighth row of the weight matrix terminates and the rownumber of the weight matrix changes from ‘8’ to ‘9’ at the step 369, theMAC arithmetic operation may terminate because the row number of ‘9’ isgreater than the last row number of ‘8’ at the step 370.

FIG. 27 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 14 , which are performed inthe PIM system 1-2 according to the second embodiment of the presentdisclosure. In order to perform the MAC arithmetic operation accordingto the present embodiment, the MAC operator 420 of the PIM device 400may have the same configuration as the MAC operator 120-1 illustrated inFIG. 16 . Referring to FIGS. 20 and 27 , the first data (i.e., theweight data) may be written into the memory bank 411 at a step 381 toperform the MAC arithmetic operation. Thus, the weight data may bestored in the memory bank 411 of the PIM device 400. In the presentembodiment, it may be assumed that the weight data are the elementsW0.0, . . . , and W7.7 constituting the weight matrix of FIG. 14 .

At a step 382, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-2 to the PIM controller 500 of thePIM system 1-2. In an embodiment, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may be in astandby mode until the inference request signal is transmitted to thePIM controller 500. Alternatively, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may performoperations (e.g., data read/write operations) other than the MACarithmetic operation in the memory mode until the inference requestsignal is transmitted to the PIM controller 500. In the presentembodiment, it may be assumed that the second data (i.e., the vectordata) are transmitted together with the inference request signal. Inaddition, it may be assumed that the vector data are the elements X0.0,. . . , and X7.0 constituting the vector matrix of FIG. 14 . If theinference request signal is transmitted to the PIM controller 500 at thestep 382, then the PIM controller 500 may write the vector datatransmitted with the inference request signal into the global buffer 412at a step 383. Accordingly, the vector data may be stored in the globalbuffer 412 of the PIM device 400.

At a step 384, an output latch of a MAC operator 420 may be initiallyset to have bias data and the initially set bias data may be fed back toan accumulative adder of the MAC operator 420. This process is executedto perform the matrix adding calculation of the MAC result matrix andthe bias matrix, which is described with reference to FIG. 14 . That is,as illustrated in FIG. 16 , the output latch 123-1 of the data outputcircuit 123-A included in the MAC operator 420 may be initially set tohave the bias data of the bias matrix. Because the matrix multiplyingcalculation is executed for the first row of the weight matrix, theelement B0.0 located at first row of the bias matrix may be initiallyset as the bias data in the output latch 123-1. The output latch 123-1may output the bias data B0.0, and the bias data B0.0 outputted from theoutput latch 123-1 may be inputted to the accumulative adder 122-21D ofthe addition logic circuit 122-2 included in the MAC operator 420.

In an embodiment, in order to output the bias data B0.0 out of theoutput latch 123-1 and to feed back the bias data B0.0 to theaccumulative adder 122-21D, the MAC command generator 540 of the PIMcontroller 500 may transmit the MAC output latch signal MAC_L3 to theMAC operator 420 of the PIM device 400. When a subsequent MAC arithmeticoperation is performed, the accumulative adder 122-21D of the MACoperator 420 may add the MAC result data MAC0.0 outputted from the adder122-21C disposed at the last stage to the bias data B0.0 which is fedback from the output latch 123-1 to generate the biased result data Y0.0and may output the biased result data Y0.0 to the output latch 123-1.The biased result data Y0.0 may be outputted from the output latch 123-1in synchronization with the MAC output latch signal MAC_L3 transmittedin a subsequent process.

At a step 385, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC read signal MAC_RD_BK to the PIMdevice 400, as illustrated in FIG. 23 . In such a case, the addressgenerator 550 of the PIM controller 500 may generate and transmit therow/column address ADDR_R/ADDR_C to the PIM device 400. The MAC readsignal MAC_RD_BK inputted to the PIM device 400 may control the dataread operation for the memory bank 411 of the PIM device 400. The memorybank 411 may output and transmit the elements W0.0, . . . , and W0.7 inthe first row of the weight matrix of the weight data stored in a regionof the memory bank 411, which is designated by the row/column addressADDR_R/ADDR_C, to the MAC operator 420 in response to the MAC readsignal MAC_RD_BK. In an embodiment, the data transmission from thememory bank 411 to the MAC operator 420 may be executed through a BIOline which is provided specifically for data transmission between thememory bank 411 and the MAC operator 420.

Meanwhile, the vector data X0.0, . . . , and X7.0 stored in the globalbuffer 412 may also be transmitted to the MAC operator 420 insynchronization with a point in time when the weight data aretransmitted from the memory bank 411 to the MAC operator 420. In orderto transmit the vector data X0.0, . . . , and X7.0 from the globalbuffer 412 to the MAC operator 420, a control signal for controlling theread operation for the global buffer 412 may be generated insynchronization with the MAC read signal MAC_RD_BK outputted from theMAC command generator 540 of the PIM controller 500. The datatransmission between the global buffer 412 and the MAC operator 420 maybe executed through a GIO line. Thus, the weight data and the vectordata may be independently transmitted to the MAC operator 420 throughtwo separate transmission lines, respectively. In an embodiment, theweight data and the vector data may be simultaneously transmitted to theMAC operator 420 through the BIO line and the GIO line, respectively.

At a step 386, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC input latch signal MAC_L1 to the PIMdevice 400, as illustrated in FIG. 24 . The MAC input latch signalMAC_L1 may control the input latch operation of the weight data and thevector data for the MAC operator 420 of the PIM device 400. The elementsW0.0, . . . , and W0.7 in the first row of the weight matrix and theelements X0.0, . . . , and X7.0 in the first column of the vector matrixmay be inputted to the MAC circuit 122 of the MAC operator 420 by theinput latch operation. The MAC circuit 122 may include the plurality ofmultipliers (e.g., the eight multipliers 122-11), the number of which isequal to the number of columns of the weight matrix and the number ofrows of the vector matrix. The elements W0.0, . . . , and W0.7 in thefirst row of the weight matrix may be inputted to the first to eighthmultipliers 122-11, respectively, and the elements X0.0, . . . , andX7.0 in the first column of the vector matrix may also be inputted tothe first to eighth multipliers 122-11, respectively.

At a step 387, the MAC circuit 122 of the MAC operator 420 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. Specifically,each of the multipliers 122-11 of the multiplication logic circuit 122-1may perform a multiplying calculation of the inputted data, and theresult data of the multiplying calculation may be inputted to theaddition logic circuit 122-2. The addition logic circuit 122-2 mayreceive output data of the multipliers 122-11 and may perform the addingcalculation of the output data of the multipliers 122-11 to output theresult data of the adding calculation to the accumulative adder 122-21D.The output data of the adder 122-21C included in the addition logiccircuit 122-2 may correspond to result data (i.e., MAC result data) ofthe MAC arithmetic operation of the first row included in the weightmatrix and the column included in the vector matrix. The accumulativeadder 122-21D may add the output data MAC0.0 of the adder 122-21C to thebias data B0.0 fed back from the output latch 123-1 and may output theresult data of the adding calculation. The output data (i.e., the biasedresult data Y0.0) of the accumulative adder 122-21D may be inputted tothe output latch 123-1 disposed in the data output circuit 123-A of theMAC operator 420.

At a step 388, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 400, as described with reference to FIG. 25 . The MAC outputlatch signal MAC_L3 may control the output latch operation for theoutput latch 123-1 of the MAC operator 420 included in the PIM device400. The output latch 123-1 of the MAC operator 420 may output thebiased result data Y0.0 according to the output latch operationperformed in synchronization with the MAC output latch signal MAC_L3.The biased result data Y0.0 outputted from the output latch 123-1 may beinputted to the transfer gate 123-2 of the data output circuit 123-A.

At a step 389, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 400, as illustrated in FIG. 26 . The MAC latch reset signalMAC_L_RST may control an output operation of the biased result data Y0.0generated by the MAC operator 420 and a reset operation of the outputlatch 123-1 included in the MAC operator 420. The transfer gate 123-2receiving the biased result data Y0.0 from the output latch 123-1 of theMAC operator 420 may be synchronized with the MAC latch reset signalMAC_L_RST to output the biased result data Y0.0. In an embodiment, thebiased result data Y0.0 outputted from the MAC operator 120 may bestored into the memory bank 411 through the BIO line in the PIM device400.

At a step 390, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed at the previous steps, the rownumber of the weight matrix may change from ‘1’ to ‘2’ at the step 390.At a step 391, whether the row number changed at the step 390 is greaterthan the row number of the last row (i.e., the eighth row) of the weightmatrix may be determined. Because the row number of the weight matrix ischanged to ‘2’ at the step 390, a process of the MAC arithmeticoperation may be fed back to the step 384.

If the process of the MAC arithmetic operation is fed back to the step384 at the step 391, the same processes as described with reference tothe steps 384 to 391 may be executed again for the increased row numberof the weight matrix. That is, as the row number of the weight matrixchanges from ‘1’ to ‘2’, the MAC arithmetic operation may be performedfor the second row of the weight matrix instead of the first row of theweight matrix with the vector matrix. If the process of the MACarithmetic operation is fed back to the step 384 at the step 391, thenthe processes from the step 384 to the step 390 may be iterativelyperformed until the MAC arithmetic operation is performed for all of therows of the weight matrix with the vector matrix. If the MAC arithmeticoperation for the eighth row of the weight matrix terminates and the rownumber of the weight matrix changes from ‘8’ to ‘9’ at the step 390,then the MAC arithmetic operation may terminate because the row numberof ‘9’ is greater than the last row number of ‘8’ at the step 391.

FIG. 28 is a flowchart illustrating processes of the MAC arithmeticoperation described with reference to FIG. 17 , which are performed inthe PIM system 1-2 according to the second embodiment of the presentdisclosure. In order to perform the MAC arithmetic operation accordingto the present embodiment, the MAC operator 420 of the PIM device 400may have the same configuration as the MAC operator 120-2 illustrated inFIG. 19 . Referring to FIGS. 19 and 28 , the first data (i.e., theweight data) may be written into the memory bank 411 at a step 601 toperform the MAC arithmetic operation. Thus, the weight data may bestored in the memory bank 411 of the PIM device 400. In the presentembodiment, it may be assumed that the weight data are the elementsW0.0, . . . , and W7.7 constituting the weight matrix of FIG. 17 .

At a step 602, whether an inference is requested may be determined. Aninference request signal may be transmitted from an external devicelocated outside of the PIM system 1-2 to the PIM controller 500 of thePIM system 1-2. In an embodiment, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may be in astandby mode until the inference request signal is transmitted to thePIM controller 500. Alternatively, if no inference request signal istransmitted to the PIM controller 500, the PIM system 1-2 may performoperations (e.g., data read/write operations) other than the MACarithmetic operation in the memory mode until the inference requestsignal is transmitted to the PIM controller 500. In the presentembodiment, it may be assumed that the second data (i.e., the vectordata) are transmitted together with the inference request signal. Inaddition, it may be assumed that the vector data are the elements X0.0,. . . , and X7.0 constituting the vector matrix of FIG. 17 . If theinference request signal is transmitted to the PIM controller 500 at thestep 602, then the PIM controller 500 may write the vector datatransmitted with the inference request signal into the global buffer 412at a step 603. Accordingly, the vector data may be stored in the globalbuffer 412 of the PIM device 400.

At a step 604, an output latch of a MAC operator 420 may be initiallyset to have bias data and the initially set bias data may be fed back toan accumulative adder of the MAC operator 420. This process is executedto perform the matrix adding calculation of the MAC result matrix andthe bias matrix, which is described with reference to FIG. 17 . That is,as described with reference to FIG. 19 , the output latch 123-1 of thedata output circuit 123-B included in the MAC operator 420 may beinitially set to have the bias data of the bias matrix. Because thematrix multiplying calculation is executed for the first row of theweight matrix, the element B0.0 located at first row of the bias matrixmay be initially set as the bias data in the output latch 123-1. Theoutput latch 123-1 may output the bias data B0.0, and the bias data B0.0outputted from the output latch 123-1 may be inputted to theaccumulative adder 122-21D of the addition logic circuit 122-2 includedin the MAC operator 420.

In an embodiment, in order to output the bias data B0.0 out of theoutput latch 123-1 and to feed back the bias data B0.0 to theaccumulative adder 122-21D, the MAC command generator 540 of the PIMcontroller 500 may transmit the MAC output latch signal MAC_L3 to theMAC operator 420 of the PIM device 400. When a subsequent MAC arithmeticoperation is performed, the accumulative adder 122-21D of the MACoperator 420 may add the MAC result data MAC0.0 outputted from the adder122-21C disposed at the last stage of the addition logic circuit 122-2to the bias data B0.0 which is fed back from the output latch 123-1 togenerate the biased result data Y0.0 and may output the biased resultdata Y0.0 to the output latch 123-1. The biased result data Y0.0 may beoutputted from the output latch 123-1 in synchronization with the MACoutput latch signal MAC_L3 transmitted in a subsequent process.

At a step 605, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC read signal MAC_RD_BK to the PIMdevice 400, as illustrated in FIG. 23 . In such a case, the addressgenerator 550 of the PIM controller 500 may generate and transmit therow/column address ADDR_R/ADDR_C to the PIM device 400. The MAC readsignal MAC_RD_BK inputted to the PIM device 400 may control the dataread operation for the memory bank 411 of the PIM device 400. The memorybank 411 may output and transmit the elements W0.0, . . . , and W0.7 inthe first row of the weight matrix of the weight data stored in a regionof the memory bank 411, which is designated by the row/column addressADDR_R/ADDR_C, to the MAC operator 420 in response to the MAC readsignal MAC_RD_BK. In an embodiment, the data transmission from thememory bank 411 to the MAC operator 420 may be executed through a BIOline which is provided specifically for data transmission between thememory bank 411 and the MAC operator 420.

Meanwhile, the vector data X0.0, . . . , and X7.0 stored in the globalbuffer 412 may also be transmitted to the MAC operator 420 insynchronization with a point in time when the weight data aretransmitted from the memory bank 411 to the MAC operator 420. In orderto transmit the vector data X0.0, . . . , and X7.0 from the globalbuffer 412 to the MAC operator 420, a control signal for controlling theread operation for the global buffer 412 may be generated insynchronization with the MAC read signal MAC_RD_BK outputted from theMAC command generator 540 of the PIM controller 500. The datatransmission between the global buffer 412 and the MAC operator 420 maybe executed through a GIO line. Thus, the weight data and the vectordata may be independently transmitted to the MAC operator 420 throughtwo separate transmission lines, respectively. In an embodiment, theweight data and the vector data may be simultaneously transmitted to theMAC operator 420 through the BIO line and the GIO line, respectively.

At a step 606, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC input latch signal MAC_L1 to the PIMdevice 400, as described with reference to FIG. 24 . The MAC input latchsignal MAC_L1 may control the input latch operation of the weight dataand the vector data for the MAC operator 420 of the PIM device 400. Theelements W0.0, . . . , and W0.7 in the first row of the weight matrixand the elements X0.0, . . . , and X7.0 in the first column of thevector matrix may be inputted to the MAC circuit 122 of the MAC operator420 by the input latch operation. The MAC circuit 122 may include theplurality of multipliers (e.g., the eight multipliers 122-11), thenumber of which is equal to the number of columns of the weight matrixand the number of rows of the vector matrix. The elements W0.0, . . . ,and W0.7 in the first row of the weight matrix may be inputted to thefirst to eighth multipliers 122-11, respectively, and the elements X0.0,. . . , and X7.0 in the first column of the vector matrix may also beinputted to the first to eighth multipliers 122-11, respectively.

At a step 607, the MAC circuit 122 of the MAC operator 420 may performthe MAC arithmetic operation of an R^(th) row of the weight matrix andthe first column of the vector matrix, which are inputted to the MACcircuit 122. An initial value of ‘R’ may be set as ‘1’. Thus, the MACarithmetic operation of the first row of the weight matrix and the firstcolumn of the vector matrix may be performed a first time. Specifically,each of the multipliers 122-11 of the multiplication logic circuit 122-1may perform a multiplying calculation of the inputted data, and theresult data of the multiplying calculation may be inputted to theaddition logic circuit 122-2. The addition logic circuit 122-2 mayreceive output data of the multipliers 122-11 and may perform the addingcalculation of the output data of the multipliers 122-11 to output theresult data of the adding calculation to the accumulative adder 122-21D.The output data of the adder 122-21C included in the addition logiccircuit 122-2 may correspond to result data (i.e., the MAC result dataMAC0.0) of the MAC arithmetic operation of the first row included in theweight matrix and the column included in the vector matrix. Theaccumulative adder 122-21D may add the output data MAC0.0 of the adder122-21C to the bias data B0.0 fed back from the output latch 123-1 andmay output the result data of the adding calculation. The output data(i.e., the biased result data Y0.0) of the accumulative adder 122-21Dmay be inputted to the output latch 123-1 disposed in the data outputcircuit 123-A of the MAC operator 420.

At a step 608, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC output latch signal MAC_L3 to the PIMdevice 400, as described with reference to FIG. 25 . The MAC outputlatch signal MAC_L3 may control the output latch operation for theoutput latch 123-1 of the MAC operator 420 included in the PIM device400. The output latch 123-1 of the MAC operator 420 may output thebiased result data Y0.0 according to the output latch operationperformed in synchronization with the MAC output latch signal MAC_L3.The biased result data Y0.0 outputted from the output latch 123-1 may beinputted to the activation function logic circuit 123-5, which isillustrated in FIG. 19 . At a step 610, the activation function logiccircuit 123-5 may apply an activation function to the biased result dataY0.0 to generate a final output value, and the final output value may beinputted to the transfer gate (123-2 of FIG. 4 ).

At a step 610, the MAC command generator 540 of the PIM controller 500may generate and transmit the MAC latch reset signal MAC_L_RST to thePIM device 400, as described with reference to FIG. 26 . The MAC latchreset signal MAC_L_RST may control an output operation of the finaloutput value generated by the MAC operator 420 and a reset operation ofthe output latch 123-1 included in the MAC operator 420. The transfergate 123-2 receiving the final output value from the activation functionlogic circuit 123-5 of the data output circuit 123-B included in the MACoperator 420 may be synchronized with the MAC latch reset signalMAC_L_RST to output the final output value. In an embodiment, the finaloutput value outputted from the MAC operator 420 may be stored into thememory bank 411 through the BIO line in the PIM device 400.

At a step 611, the row number ‘R’ of the weight matrix for which the MACarithmetic operation is performed may be increased by ‘1’. Because theMAC arithmetic operation for the first row among the first to eight rowsof the weight matrix has been performed at the previous steps, the rownumber of the weight matrix may change from ‘1’ to ‘2’ at the step 611.At a step 612, whether the row number changed at the step 611 is greaterthan the row number of the last row (i.e., the eighth row) of the weightmatrix may be determined. Because the row number of the weight matrix ischanged to ‘2’ at the step 611, a process of the MAC arithmeticoperation may be fed back to the step 604.

If the process of the MAC arithmetic operation is fed back to the step604 from the step 612, the same processes as described with reference tothe steps 604 to 612 may be executed again for the increased row numberof the weight matrix. That is, as the row number of the weight matrixchanges from ‘1’ to ‘2’, the MAC arithmetic operation may be performedfor the second row of the weight matrix instead of the first row of theweight matrix with the vector matrix to generate the MAC result data(corresponding to the element MAC1.0 located in the second row of theMAC result matrix) and the bias data (corresponding to the element B1.0located in the second row of the bias matrix). If the process of the MACarithmetic operation is fed back to the step 604 from the step 612, theprocesses from the step 604 to the step 612 may be iteratively performeduntil the MAC arithmetic operation is performed for all of the rows(i.e., first to eighth rows) of the weight matrix with the vectormatrix. If the MAC arithmetic operation for the eighth row of the weightmatrix terminates and the row number of the weight matrix changes from‘8’ to ‘9’ at the step 611, the MAC arithmetic operation may terminatebecause the row number of ‘9’ is greater than the last row number of ‘8’at the step 612.

FIG. 29 is a block diagram illustrating a PIM system 1-3 according to athird embodiment of the present disclosure. As illustrated in FIG. 29 ,the PIM system 1-3 may have substantially the same configuration as thePIM system 1-1 illustrated in FIG. 2 except that a PIM controller 200Aof the PIM system 1-3 further includes a mode register set (MRS) 260 ascompared with the PIM controller 200 of the PIM system 1-1. Thus, thesame explanation as described with reference to FIG. 2 will be omittedhereinafter. The mode register set 260 in the PIM controller 200A mayreceive an MRS signal instructing arrangement of various signalsnecessary for the MAC arithmetic operation of the PIM system 1-3. In anembodiment, the mode register set 260 may receive the MRS signal fromthe mode selector 221 included in the scheduler 220. However, in anotherembodiment, the MRS signal may be provided by an extra logic circuitother than the mode selector 221. The mode register set 260 receivingthe MRS signal may transmit the MRS signal to the MAC command generator240. For an embodiment, the MRS 260 represents a MRS circuit.

In an embodiment, the MRS signal may include timing information on whenthe MAC commands MAC_CMDs are generated. In such a case, thedeterministic operation of the PIM system 1-3 may be performed by theMRS signal provided by the MRS 260. In another embodiment, the MRSsignal may include information on the timing related to an intervalbetween the MAC modes or information on a mode change between the MACmode and the memory mode. In an embodiment, generation of the MRS signalin the MRS 260 may be executed before the vector data are stored in thesecond memory bank 112 of the PIM device 100 by the inference requestsignal transmitted from an external device to the PIM controller 200A.Alternatively, the generation of the MRS signal in the MRS 260 may beexecuted after the vector data are stored in the second memory bank 112of the PIM device 100 by the inference request signal transmitted froman external device to the PIM controller 200A.

FIG. 30 is a block diagram illustrating a PIM system 1-4 according to afourth embodiment of the present disclosure. As illustrated in FIG. 30 ,the PIM system 1-4 may have substantially the same configuration as thePIM system 1-2 illustrated in FIG. 20 except that a PIM controller 500Aof the PIM system 1-4 further includes the mode register set (MRS) 260as compared with the PIM controller 500 of the PIM system 1-2. Thus, thesame explanation as described with reference to FIG. 20 will be omittedhereinafter. The mode register set 260 in the PIM controller 500A mayreceive an MRS signal instructing arrangement of various signalsnecessary for the MAC arithmetic operation of the PIM system 1-4. In anembodiment, the mode register set 260 may receive the MRS signal fromthe mode selector 221 included in the scheduler 220. However, in anotherembodiment, the MRS signal may be provided by an extra logic circuitother than the mode selector 221. The mode register set 260 receivingthe MRS signal may transmit the MRS signal to the MAC command generator540.

In an embodiment, the MRS signal may include timing information on whenthe MAC commands MAC_CMDs are generated. In such a case, thedeterministic operation of the PIM system 1-4 may be performed by theMRS signal provided by the MRS 260. In another embodiment, the MRSsignal may include information on the timing related to an intervalbetween the MAC modes or information on a mode change between the MACmode and the memory mode. In an embodiment, generation of the MRS signalin the MRS 260 may be executed before the vector data are stored in theglobal buffer 412 of the PIM device 400 by the inference request signaltransmitted from an external device to the PIM controller 500A.Alternatively, the generation of the MRS signal in the MRS 260 may beexecuted after the vector data are stored in the global buffer 412 ofthe PIM device 400 by the inference request signal transmitted from anexternal device to the PIM controller 500A.

A limited number of possible embodiments for the present teachings havebeen presented above for illustrative purposes. Those of ordinary skillin the art will appreciate that various modifications, additions, andsubstitutions are possible. While this patent document contains manyspecifics, these should not be construed as limitations on the scope ofthe present teachings or of what may be claimed, but rather asdescriptions of features that may be specific to particular embodiments.Certain features that are described in this patent document in thecontext of separate embodiments can also be implemented in combinationin a single embodiment. Conversely, various features that are describedin the context of a single embodiment can also be implemented inmultiple embodiments separately or in any suitable subcombination.Moreover, although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

What is claimed is:
 1. A processing-in-memory (PIM) system comprising: aPIM device including a storage region, a global buffer, and amultiplication/accumulation (MAC) operator, wherein the MAC operator issuitable for receiving first data and second data from the storageregion and the global buffer, respectively, to perform a MAC arithmeticoperation; a PIM controller configured to control a memory mode and aMAC mode of the PIM device; a bank input/output (BIO) line providing afirst data transmission path for the first data between the storageregion and the MAC operator; and a global input/output (GIO) lineproviding a second data transmission path for the second data betweenthe global buffer and the MAC operator, wherein the PIM controller isconfigured to generate and transmit a memory command to the PIM devicein the memory mode, and wherein the PIM controller is configured togenerate and transmit first, second, and third (first to third) MACcommands to the PIM device in the MAC mode.
 2. The PIM system of claim1, wherein the MAC arithmetic operation is a deterministic MACarithmetic operation performed during a predetermined fixed time.
 3. ThePIM system of claim 1, wherein the PIM controller includes: a memorycommand generator configured to generate and output the memory commandin the memory mode; and a MAC command generator configured to generateand output the first to third MAC commands in the MAC mode.
 4. The PIMsystem of claim 3, wherein the MAC command generator is configured tosequentially output the first to third MAC commands with predeterminedtime intervals.
 5. The PIM system of claim 3, wherein the first MACcommand is a first control signal for reading the first data out of thestorage region; wherein the second MAC command is a second controlsignal for latching the first and second data in the MAC operator; andwherein the third MAC command is a third control signal for latching MACresult data of the MAC operator.
 6. The PIM system of claim 5, whereinthe MAC command generator is configured to: output the first MAC commandat a first point in time; output the second MAC command at a secondpoint in time when a first latency elapses from the first point in time;and output the third MAC command at a third point in time when a secondlatency elapses from the second point in time.
 7. The PIM system ofclaim 6, wherein the first latency is set as a time it takes to read thefirst data out of the storage region based on the first MAC command andto output the first data to the MAC operator; and wherein the secondlatency is set as a time it takes to latch the first data and the seconddata in the MAC operator based on the second MAC command and to performthe MAC arithmetic operation of the first and second data which arelatched in the MAC operator.
 8. The PIM system of claim 7, wherein theMAC operator includes: a data input circuit configured to receive thefirst and second data from the storage region and the global buffer,respectively, and configured to latch the first and second data insynchronization with the second MAC command; a MAC circuit configured toreceive the first and second data latched by the data input circuit andconfigured to perform the MAC arithmetic operation of the first andsecond data to output MAC result data; and a data output circuitincluding an output latch for receiving and latching the MAC result dataoutputted from the MAC circuit in synchronization with the third MACcommand.
 9. The PIM system of claim 8, wherein the data output circuitfurther includes a transfer gate for transferring the MAC result data toa data transmission line in the PIM device.
 10. The PIM system of claim3, wherein the MAC command generator is configured to output a fourthMAC command after a predetermined fixed time elapses from a point intime when the third MAC command is outputted from the MAC commandgenerator.
 11. The PIM system of claim 10, wherein the fourth MACcommand is a fourth control signal for outputting the MAC result datafrom the MAC operator and for resetting an output latch included in theMAC operator.
 12. The PIM system of claim 11, wherein the MAC commandgenerator is configured to: output the first MAC command at a firstpoint in time; output the second MAC command at a second point in timewhen a first latency elapses from the first point in time; output thethird MAC command at a third point in time when a second latency elapsesfrom the second point in time; and output the fourth MAC command at afourth point in time when a third latency elapses from the third pointin time.
 13. The PIM system of claim 12, wherein the first latency isset as a time it takes to read the first data out of the storage regionbased on the first MAC command and to output the first data to the MACoperator; wherein the second latency is set as a time it takes to latchthe first data and the second data in the MAC operator based on thesecond MAC command and to perform the MAC arithmetic operation of thefirst and second data which are latched in the MAC operator; and whereinthe third latency is set as a time it takes to perform an output latchoperation of MAC result data generated by the MAC arithmetic operation.14. The PIM system of claim 3, wherein the PIM controller furtherincludes: command queue logic configured to store a command queueoutputted from an external device; and a scheduler configured to adjusta timing when the command queue stored in the command queue logic isoutputted from the command queue logic.
 15. The PIM system of claim 14,wherein the scheduler includes a mode selector configured to generate amode selection signal including information on whether the command queueoutputted from the command queue logic relates to the memory mode or theMAC mode.
 16. The PIM system of claim 14, wherein the command queuelogic is further configured to: transmit the command queue to the memorycommand generator in response to a fourth control signal outputted fromthe scheduler when the command queue relates to the memory mode; andtransmit the command queue to the MAC command generator in response tothe control signal outputted from the scheduler when the command queuerelates to the MAC mode.
 17. The PIM system of claim 3, wherein the PIMcontroller further includes a mode register set for arranging signalsused for the MAC arithmetic operation.
 18. The PIM system of claim 17,wherein arranging the signals used for the MAC arithmetic operationincludes setting timings when the first to fifth MAC commands aregenerated.
 19. The PIM system of claim 17, wherein arranging the signalsused for the MAC arithmetic operation is executed based on informationabout timing related to an interval between the MAC modes or informationabout a mode change between the MAC mode and the memory mode.